Poll: Donald Trump still leads the GOP field

With the presidential primaries in full swing, Donald Trump maintains his sizable lead over the rest of the Republican field. Among Republican or Republican-leaning registered voters, Trump has 35% support compared to 18% for Ted Cruz and 13% for Marco Rubio, according to results from the latest NBC NewsSurveyMonkey Weekly Election Tracking Poll for the week of December 28, 2015 through January 3, 2016. The poll was conducted online among a national sample of 3,700 adults aged 18 and over.

See some of Donald Trump's biggest supporters:

Trump leads among men with 39% of support, compared to 21% of men who support Cruz and 13% of men who support Rubio. Trump also leads among women with 29% support, while Cruz and Rubio have about equal support from women—13% and 14%, respectively.

Perhaps surprisingly, Trump also has the highest support among white evangelical voters—33%. Although Ben Carson did fairly well among white evangelicals (12%), the group heavily favored Trump. Cruz also did well with white evangelicals, with 2 in 10 supporting him. Rubio's support among this group was 1 in 10. Republican-leaned voters who describe their political views as "very conservative" are most likely to support Trump (35%) and Cruz (30%) with the other candidates at least 20 points behind.

A big question in the election is whether Trump supporters will change their minds. Our results show that half of Trump voters (51%) say they are absolutely certain they will vote for him. Another 3 in 10 Trump supporters say there is a large chance they will vote for him. Cruz and Rubio supporters, however, are not as certain that they will vote for their candidate. Just under half (49%) of both candidates' supporters say there is a large chance they will vote for their candidate but they are not absolutely certain.

Graphics by Sam Petulla.

More from NBC News:
'Affluenza' Teen's Lawyer Hints at Human Rights Issues
One Year Later, Charlie Hebdo Proves It's Very Much Alive
Rare Set of Identical Triplets Heads Home From Hospital