In this particular poll, Trump has hit an all-time high of 36% support beating out Ted Cruz by a full 17 points. The trend continues in an upward trajectory according to the last few months.
From CBS News:
Heading into the early primary contests, Donald Trump continues to hold a double digit lead over the rest of the Republican field nationally. Thirty-six percent of Republican primary voters support Trump, 17 points ahead of his closest rival, Texas Senator Ted Cruz (19 percent). Florida Senator Marco Rubio has now climbed to third place at 12 percent. Ben Carson — who briefly surged to the top of the field at the end of October — is tied with former Florida Governor Jeb Bush at 6 percent.
Cruz and Rubio have risen as well, but that’s because voters are finally abandoning the rest of the field. Trump hasn’t lost the national lead since the short insurgence of Ben Carson back in October. By these accounts, he’s in the best position to become the nominee with deep support from coast to coast.