From CBS News:
Thirty-five percent of Republican primary voters support Trump, up 13 points since October, and his highest level of support in CBS News polling. Ted Cruz (16 percent) has moved into second place, while Ben Carson, who led the October poll, has dropped to third.
Marco Rubio is in fourth place with 9 percent. Jeb Bush is getting the backing of just 3 percent of Republican primary voters nationwide, his lowest percentage to date in CBS News polling. Carly Fiorina's support has also dropped; she is at just 1 percent now.