NEW YORK (AP) -- Ken Griffey Jr. was elected to baseball's Hall of Fame on Wednesday with the highest voting percentage ever, and Mike Piazza will join him in Cooperstown this summer.
A star slugger of the Steroids Era never tainted by accusations of drug use, Griffey was on 437 of 440 votes in his first appearance on the Baseball Writers' Association of America ballot. His 99.3 percentage topped the previous mark of 98.84, set when Tom Seaver appeared on 425 of 430 ballots in 1992.
There had been speculation Griffey could become the first unanimous selection.
"I can't be upset. It's just an honor to be elected and to have the highest percentage is definitely a shock," Griffey said on a conference call.
After falling 28 shy last year, Piazza received 365 votes in his fourth time on the ballot and will be inducted along with Griffey on July 24.
"Incredibly special. Wow," Piazza said on a call with MLB Network.
"I sat here with my mouth on the floor," he said.
A player needs 75 percent to gain election, and Jeff Bagwell missed by 15 votes and Tim Raines by 23. Trevor Hoffman, on the ballot for the first time, was 34 short.
The vote total dropped by 109 from last year because writers who have not been active for 10 years lost their votes under new rules.
KEN GRIFFEY JR. THROUGH THE YEARS:
Ken Griffey Jr. through his career
Ken Griffey Jr., Mike Piazza elected to the Baseball Hall of Fame
Former Cincinnati Reds center fielders Ken Griffey Jr., right, and Cesar Geronimo hug in ceremonies after a baseball game between the Reds and the Miami Marlins, Friday, Aug. 8, 2014, in Cincinnati. Griffey will be inducted into the Reds Hall of Fame, Saturday. (AP Photo/Al Behrman)
BALTIMORE, MD - AUGUST 1: Ken Griffey Jr. #24 of the Seattle Mariners before a baseball game against the Baltimore Orioles on August 1, 1989 at Memorial Stadium in Baltimore, Maryland. (Photo by Mitchell Layton/Getty Images)
Ken Griffey Jr. of the Seattle Mariners eyes the approaching pitch from Texas Ranger pitcher Charlie Hough during the 7th inning just before he unloads to send the ball into the right field seats to notch his 10th homerun of the year and break a 1-1 tie in Seattle, June 5, 1989. (AP Photo/Robert Kaiser)
CIRCA 1990: Outfielder Ken Griffey Jr. #24 of the Seattle Mariners poses for this portrait circa 1990 before a Major League Baseball game. Griffey played for the Mariners from 1989-99 and 2009-2010. (Photo by Focus on Sport/Getty Images)
1993: Ken Griffey Jr. #24 of the Seattle Mariners looks on during a game in the 1993 season. (Photo by Andy Hayt/Getty Images)
Seattle Mariners' Ken Griffey Jr. smiles from beneath a pile of teammates who mobbed him after he scored the winning run in the bottom of the 11th inning against the New York Yankees Sunday, Oct. 8, 1995 in Seattle. The Mariners won 6-5. (AP Photo/Elaine Thompson)
Seattle Marinersâ Ken Griffey Jr. flips his bat after srawing a walk during the ninth inning against the California Angels in Anaheim, Calif. on Wednesday, Sept. 25, 1996. (AP Photo/Michael Caulfield)
Ken Griffey Jr. holds up a Cincinnati Reds jersey at a news conference in Cincinnati, Thursday, Feb. 10, 2000, after agreeing to a nine-year contract worth $116.5 million with the Reds, the richest package in baseball history. (AP Photo/Al Behrman)
Cincinnati Reds center fielder Ken Griffey Jr., prepares for Monday's Graperfruit League game against the Tampa Bay Devil Rays March 11, 2002 in Sarasota, Fla..(AP Photo/Gene J. Puskar)
Pittsburgh Pirates new center fielder Kenny Lofton is grabbed by Cincinnati Reds center fielder Ken Griffey Jr., during pre-game warm ups before Thursday Grapefruit League action Thursday, March 20, 2003 in Sarasota, Fla.. It was Lofton's first major league action since coming to the Pirates last week.(AP Photo/Gene J. Puskar)
Cincinnati Reds' radio announcer Joe Nuxhall, right, presents Ken Griffey Jr. a crystal plaque for his 500th career home run during a ceremony prior to their game with the Pittsburgh Pirates at Great American Ball Park, Friday, June 25, 2004, in Cincinnati. (AP Photo/Tom Uhlman)
HOUSTON - JULY 12: Ken Griffey Jr. & son Trey look on during the 2004 All-Star Game Home Run Derby at Minute Maid Field on July 12, 2004 in Houston TX. (Photo by Rich Pilling/ MLB Photos via Getty Images).
KRT SPORTS STORY SLUGGED: BBN-REDS-NATIONALS KRT PHOTOGRAPH BY CHUCK KENNEDY/KRT (August 25) WASHINGTON, DC -- Cincinnati's Ken Griffey Jr. bats in the seventh inning against Washington on Thursday, August 25, 2005. (Photo by Chuck Kennedy/MCT/MCT via Getty Images)
SARASOTA, FL - FEBRUARY 24: Ken Griffey Jr. #3 poses during Cincinnati Reds photo day on February 24, 2006 at Ed Smith Stadium in Sarasota, Florida. (Photo by Jamie Squire/Getty Images)
Cincinnati Reds' Ken Griffey Jr. is congratulated after hitting a solo home run off Chicago Cubs pitcher Carlos Zambrano in the eighth inning of a baseball game Saturday, June 10, 2006, in Cincinnati. (AP Photo/David Kohl)
Cincinnati Reds' Ken Griffey Jr. smiles in the dugout during the Reds 6-2 loss to the Philadelphia Phillies in a spring training baseball game in Clearwater, Fla., Tuesday, March 27, 2007. (AP Photo/Kathy Willens)
Cincinnati Reds right fielder Ken Griffey Jr. can't make a sliding catch on a single by Houston Astros' Mark Loretta in the seventh inning of the Astros' 10-2 win in a baseball game Thursday, May 31, 2007, in Houston. (AP Photo/Pat Sullivan)
As rain drops begin to fall, Cincinnati Reds' Ken Griffey Jr. waits on the dugout rail during an MLB baseball game against the Seattle Mariners Sunday, June 24, 2007, at Safeco Field in Seattle. (AP Photo/Ted S. Warren)
Newly acquired Chicago White Sox player Ken Griffey Jr. talks to the reporters during a press conference in Chicago, Tuesday, Aug. 5, 2008. (AP Photo/Paul Beaty)
Chicago White Sox's Ken Griffey Jr. watches his RBI single during the second inning of a baseball game against the Kansas City Royals on Friday, Aug. 1, 2008, in Kansas City, Mo. (AP Photo/Charlie Riedel)
Seattle Mariners' Ken Griffey Jr. hits a two-run home run against the Oakland Athletics in the fifth inning of a baseball game Monday, Aug. 24, 2009, in Seattle. (AP Photo/Elaine Thompson)
FILE - In this Oct. 4, 2009, file photo, Seattle Mariners' Ken Griffey Jr. is carried around the field by Ryan Langerhans, left, and Matt Tuiasosopo, right, after the Mariners' 4-3 win over the Texas Rangers in a baseball game in Seattle. Ken Griffey Jr. seems assured of election to the Baseball hall of Fame on the first try Wednesday, Jan. 6, 2016, possibly with a record vote of close to 100 percent. Mike Piazza, Jeff Bagwell and Tim Raines also were strong candidates to gain the 75 percent needed for baseball's highest honor. (AP Photo/John Froschauer, File)
Seattle Mariners' Ken Griffey Jr. in dugout during a baseball game Monday, April 19, 2010, in Seattle. (AP Photo/Elaine Thompson)
Ken Griffey, Jr, right, poses with Baseball Commissioner Bud Selig after Griffey received the Commissionerâs Historic Achievement Award before Game 4 of baseball's World Series between the St. Louis Cardinals and the Texas Rangers Sunday, Oct. 23, 2011, in Arlington, Texas. (AP Photo/Darron Cummings)
Ken Griffey, Jr. (top R), former Major League Baseball outfielder and Seattle Mariners special consultant, laughs at a baseball clinic for Japanese boys at Yomiuri Giants Stadium in Kawasaki, suburban Tokyo on January 15, 2012. The Mariners are scheduled to open the 2012 regular season with two games against the Oakland Aâs at the Tokyo Dome on March 28-29 in Japan. AFP PHOTO / KAZUHIRO NOGI (Photo credit should read KAZUHIRO NOGI/AFP/Getty Images)
SEATTLE, WA - AUGUST 10: Former Mariners great, Ken Griffey Jr. speaks to the crowd during a ceremony inducting him into the Seattle Mariners Hall of Fame prior to the game against the Milwaukee Brewers at Safeco Field on August 10, 2013 in Seattle, Washington. (Photo by Otto Greule Jr/Getty Images)
GLENDALE, AZ - DECEMBER 31: Former Major League Baseball player Ken Griffey Jr (R) talks with ESPN reporter Pedro Gomez as he photographs the Vizio Fiesta Bowl between the Arizona Wildcats and the Boise State Broncos at University of Phoenix Stadium on December 31, 2014 in Glendale, Arizona. (Photo by Christian Petersen/Getty Images)
CINCINNATI, OH - JULY 13: Ken Griffey Jr. walls out to throw the first pitch prior to the Gillette Home Run Derby presented by Head & Shoulders at the Great American Ball Park on July 13, 2015 in Cincinnati, Ohio. (Photo by Elsa/Getty Images)
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There were significant increases for a pair of stars accused of steroids use. Roger Clemens rose to 45 percent and Barry Bonds to 44 percent, both up from about 37 percent last year.
Mark McGwire, who admitted using steroids, received 12 percent in his 10th and final ballot appearance.
"They were Hall of Famers before all this stuff started," Griffey said on MLB Network.
Half of baseball's top 10 home run hitters are not in the Hall: Bonds (762), Alex Rodriguez (654), Jim Thome (612), Sosa (609) and McGwire (583). Rodriguez, who served a yearlong drug suspension in 2014, remains active. Thome's first appearance on the ballot will be in 2018.
Curt Schilling rose from 39 percent to 52, Edgar Martinez from 27 percent to 43 and Mike Mussina from 25 percent to 43.
Griffey was known simply as "Junior" by many as a contrast to his father, three-time All-Star outfielder Ken Griffey, who played alongside him in Seattle during 1990 and '91. The younger Griffey became a 13-time All-Star outfielder and finished with 630 homers, which is sixth on the career list. After reaching the major leagues in 1989, he was selected for 11 consecutive All-Star Games in 1990.
Now, he's headed to Cooperstown.
"In case you don't know, I'm really superstitious. I've played in the Hall of Fame game three times and I've never set foot in the building. I've never even seen the front of it," Griffey said. "The one time I wanted to go in there, I wanted to be a member."
Wanting to play closer to his home in Florida, he pushed for a trade to Cincinnati - his father's old team and the area he grew up in- after the 1999 season. But slowed by injuries, he never reached 100 RBIs again after his first season with the Reds, and he moved on to the Chicago White Sox in 2008 before spending his last season-plus with the Mariners.
While Griffey was selected first in the 1987 amateur draft and became the first No. 1 to make the Hall, Piazza was selected by the Los Angeles Dodgers with the 1,390th pick on the 62nd round in 1998. Since the draft started in 1965, the lowest draft pick elected to the Hall was John Smoltz, taken with selection 574 on the 22nd round in 1985.
Piazza became the top offensive catcher in big league history, hitting better than .300 in nine straight seasons and finishing with 427 home runs, including a record 396 when he was in the game behind the plate. He was a 12-time All-Star with a .308 career batting average.
MIKE PIAZZA THROUGH THE YEARS:
Mike Piazza through his career
Ken Griffey Jr., Mike Piazza elected to the Baseball Hall of Fame
NEW YORK, NY - OCTOBER 30: Former New York Mets Mike Piazza waves before throwing out the first pitch prior to Game Three of the 2015 World Series between the New York Mets and the Kansas City Royals at Citi Field on October 30, 2015 in New York City. (Photo by Mike Stobe/Getty Images)
24 Jul 1993: Catcher Mike Piazza of the Los Angeles Dodgers looks on during a game against the Houston Astros at Dodger Stadium in Los Angeles, California. Mandatory Credit: Jed Jacobsohn /Allsport
Los Angeles Dodgers catcher Mike Piazza rounds the bases after hitting a two-run home run during the fifth inning of their game against the San Francisco Giants, June 28, 1994, in Los Angeles. Dodgers won, 7-4. (AP Photo/Mark J. Terrill)
Los Angeles Dodgers' Mike Piazza, right, celebrates with a bottle of champagne after the Dodgers clinched the National League West Saturday Sept. 30, 1995 in San Diego. Los Angeles, in first place when the strike ended last season, hadn't been in the playoffs since 1988. That year, they also clinched the division title in San Diego and went on to beat Oakland in the World Series. (AP Photo/Sandy Huffaker)
Los Angeles Dodgers' catcher Mike Piazza fires a throw to first after stepping on homeplate for a force out and then completing a double play as San Diego Padres' Scott Livingstone slides in during the first inning of the Dodgers game against the San Diego Padres Wednesday July 3, 1996 in San Diego. Piazza had fielded a swinging bunt with the bases loaded and completed the double play to end a Padres' threat. (AP Photo/Lenny Ignelzi)
Former Los Angeles Dodgers' manager and Baseball Hall of Fame member Tommy Lasorda shares a moment with his godson, Mike Piazza, prior to a ceremony to retire his jersey Friday, Aug. 15, 1997, in Los Angeles. (AP Photo/Mark J. Terrill)
New York Mets catcher Mike Piazza, center, smiles with Mets owners Nelson Doubleday, left, and Fred Wilpon, after the press conference about Piazza's record seven-year $91 million dollar contract with the Mets at New York's Shea Stadium on Monday, Oct 26, 1996. Piazza signed the most lucrative player-contract in the history of major league baseball. (AP Photo/Adam Nadel)
New York Mets' Mike Piazza, right, is congratulated by Rickey Henderson (24) after hitting a three-run home run off New York Yankees' Ramiro Mendoza in the seventh inning of their interleague game Saturday, July 10, 1999 at Shea Stadium in New York. The blast was Piazza's second three-run homer in two days. The Mets went on to defeat the Yankees 9-8 and are up two games to none in the three game series. (AP Photo/John Dunn)
New York Mets' catcher Mike Piazza smiles during team batting practice at Boston's Fenway Park, Thursday, July 13, 2000. Piazza is to play against the Boston Red Sox Thursday in his first game since being hit in the head on a pitch by New York Yankees Roger Clemens. (AP Photo/Steven Senne)
New York Mets catcher Mike Piazza looks at the ball after a late throw to home allowing to runs to score off Chicago Cubs' Gary Matthews Jr. two-run double in the seventh inning Tuesday June 26, 2001 in Chicago. The Cubs defeated the Mets 4-2.(AP Photo/M. Spencer Green)
New York Mets' Mike Piazza points to cheering Mets fans at Wrigley Field after the Mets beat the Chicago Cubs 3-2 Wednesday, April 10, 2002 in Chicago. (AP Photo/Ted S. Warren)
New York Mets catcher Mike Piazza sits dejectedly on the bench after the Mets gave up four runs to the Colorado Rockies in the third inning in Coors Field in Denver on Friday, Aug. 23, 2002. (AP Photo/David Zalubowski)
New York Mets catcher Mike Piazza signs autographs prior to the game against Montreal Expos, Monday, April 14, 2003 at the Hiram Bithorn Stadium in San Juan, Puerto Rico. (AP Photo/Andres Leighton)
New York Mets catcher Mike Piazza is greeted with high fives by teammates after scoring on a Tony Clark single in the first inning against the San Francisco Giants at Pacific Bell Park, Thursday May 15, 2003, in San Francisco. (AP Photo/George Nikitin)
New York Mets' Mike Piazza reacts after Milwaukee Bruins Scott Podsednik scored in the seventh inning at New York's Shea Stadium Friday, May 7, 2004. (AP Photo/Frank Franklin II)
Hall of Fame catchers Gary Carter, far left, Johnny Bench, second from left, Carlton Fiskthird from left, and Yogi Berra, second from right, pose with New York Mets' Mike Piazza (31) Friday, June 18, 2004, at Shea Stadium in New York. Piazza was honored in a pre-game ceremony for breaking the all-time home run mark by catchers. Detroit Tigers' catcher Ivan Rodriguez is at right. (AP Photo/Bill Kostroun)
New York Mets catcher Mike Piazza sights the ball during spring training practice in Port St. Lucie, Fla., Friday, Feb. 18, 2005, on the first day of pitchers and catchers workouts. (AP Photo/Richard Drew)
New York Mets' Mike Piazza reacts after being told that he did not score after crossing home against the Seattle Mariners in the second inning, Saturday, June 18, 2005, in Seattle. Piazza, who walked earlier in the inning, failed to get to home before teammate David Wright was thrown out while trying to advance to third base for the final out. (AP Photo/Elaine Thompson)
New York Mets catcher Mike Piazza acknowledges fans during the seventh inning against the Colorado Rockies at Shea Stadium in New York, Sunday, Oct. 2, 2005. (AP Photo/Ed Betz)
San Diego Padres catcher Mike Piazza tosses a ball at baseball spring training for pitchers and catchers, Wednesday, Feb. 22, 2006, in Peoria, Ariz. (AP Photo/Elaine Thompson)
San Diego Padres catcher Mike Piazza smiles in the dugout before the spring training exhibition baseball against the Texas Rangers in Surprise, Ariz., Wednesday, March 29, 2006. (AP Photo/LM Otero)
San Diego Padres catcher Mike Piazza, left, reaches out to put the tag on Colorado Rockies' Yorvit Torrealba as he tried to score on a ground ball by Cory Sullivan in the fourth inning of the Rockies' 9-8 victory in 10 innings in a baseball game in Denver on Thursday, July 27, 2006. (AP Photo/David Zalubowski)
San Diego Padres catcher Mike Piazza tips his hat before a baseball game against his former team, the New York Mets, Tuesday, Aug. 8, 2006 at Shea Stadium in New York. (AP Photo/Ed Betz)
Oakland Athletics' designated hitter Mike Piazza, second from right, during the national anthem before their baseball game against the Los Angeles Angels in Oakland, Calif., Sunday, Sept. 30, 2007.(AP Photo/Eric Risberg)
Italy hitting coach Mike Piazza adjusts his hat during an exhibition spring training baseball game against the Los Angeles Angels Wednesday, March 6, 2013, in Tempe, Ariz. (AP Photo/Morry Gash)
Former New York Mets catcher Mike Piazza gestures as he says the fans were "number one" in supporting him during his career, as he speaks during a Mets Hall of Fame induction ceremony, Sunday, Sept. 29, 2013, in New York. (AP Photo/Kathy Willens)
FILE - In this Oct. 30, 2015, file photo, former New York Mets' Mike Piazza throws out the first pitch before Game 3 of the Major League Baseball World Series against the Kansas City Royals, in New York. Ken Griffey Jr. seems assured of election to the Baseball hall of Fame on the first try Wednesday, Jan. 6, 2016, possibly with a record vote of close to 100 percent. Mike Piazza, Jeff Bagwell and Tim Raines also were strong candidates to gain the 75 percent needed for baseball's highest honor. (AP Photo/Brad Penner, Pool via AP, File)
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After reaching the major leagues with the Dodgers in 1992, Piazza was dealt to Florida in May 1998 before he could become a free agent, then traded eight days later to the Mets. He remained with New York through 2005, hitting a memorable go-ahead home-run in the first game in the city following the 2001 terrorist attacks, then finished with San Diego in 2006 and Oakland the following year.
Piazza and Bagwell were drawn into the steroids controversy by some who pointed out their powerful physiques, but both have denied using performance-enhancing drugs and no substantive accusations have been made.
NOTES: Alan Trammell received 41 percent in his final ballot appearance.