CNN  — 

Former President Donald Trump holds a wide lead over his Republican presidential competitors among likely GOP caucusgoers in Iowa, the final Des Moines Register/NBC News/Mediacom poll before Monday’s caucuses found.

Overall, 48% of likely caucusgoers say Trump would be their first choice, 20% name former South Carolina Gov. Nikki Haley, and 16% Florida Gov. Ron DeSantis, with the rest of the field below 10%.

Trump stood at 51% in the December DMR/NBC poll and 43% in October, with his chief rivals in the teens in both of those prior polls.

Haley’s numerical move to second place is within the margin of error. Neither her support nor DeSantis’s has changed significantly since the December poll, when DeSantis stood at 19% to Haley’s 16% in a survey with a 4.4 point error margin.

In this poll, Haley faces a sizable enthusiasm gap compared with Trump or DeSantis. While majorities of their supporters say they are enthusiastic about their candidates, only about 4 in 10 of hers say the same.

Overall, roughly two-thirds of likely caucusgoers – 68% – say their minds are made up about whom to support. The poll was fielded among 705 likely GOP caucusgoers during the final stretch of campaigning from January 7 to January 12, with Trump’s backers far more likely to say they are committed to their candidate than those supporting other candidates.

About 8 in 10 Trump supporters – 82% – say their minds are made up, up from December when 70% said they were locked in. Fewer Haley backers, 63%, or DeSantis supporters, 64%, are similarly locked in, though both have solidified a majority of their supporters for the first time in the NBC/DMR poll’s tracking of this measure.

And Trump’s backers are likewise more enthusiastic about supporting him than are supporters of either Haley or DeSantis. While 88% of Trump-backing likely caucusgoers say they are extremely or very enthusiastic about him, a smaller majority of DeSantis backers – 62% – feel the same way and just 39% of Haley’s supporters in Iowa express that level of enthusiasm for her.

Trump’s dominant position carries through major demographic and political divides. His support stands above 50% among likely caucusgoers without college degrees (59%), registered Republicans (54%), evangelical Christians (51%) and those who would be attending for the first time (56%).

Haley performs somewhat better than her overall standing among independents (33% support her, compared with 37% who back Trump) and college graduates (27%, compared with 34% for Trump), while DeSantis support is somewhat higher than his statewide position among evangelical Christians (22%).

The poll also finds Trump with the highest favorability ratings in the field; 69% hold a favorable view of the former president, compared with 58% who view DeSantis favorably, 52% who have a favorable view of Vivek Ramaswamy and 48% who have a favorable view of Haley.

The final Iowa Poll from the Register in 2016 found Trump with 28% support to Texas Sen. Ted Cruz’s 23%, with Florida Sen. Marco Rubio at 15%. Cruz edged Trump 28% to 24%, with Rubio at 23%, in the final results from that year’s Iowa caucuses.

The DMR/NBC/Mediacom poll was conducted by telephone January 7 to 12 among a random sample of 705 likely Republican caucusgoers. Results for the full sample of likely caucusgoers has an error margin of plus or minus 3.7 percentage points.

This story has been updated with additional information.