Check out this interactive poll graph at Reuters:
http://polling.reuters.com/#poll/TR131/dates/20160207-20160212/type/day
"...On Sunday, a new CBS poll shows that Sanders has cut into Clinton's lead in South Carolina, now trailing by just 19 points with less than two weeks to go. Though still a substantial lead for the frontrunner, that is a far cry from the more than 50-point lead she once enjoyed. The poll shows Clinton leading 59 percent to 40 percent, with a margin of error of +/-8.7 percent. The latest poll showed a significant block for Sanders may still be name recognition as only 44 percent of those surveyed could say they know him "very well," compared to 70 percent who could say that of Clinton.
At the same time,
new national poll by Reuters, released Friday, is the latest showing that Sanders and Clinton are running essentially neck-and-neck across the country. But with many now focused on the upcoming Nevada caucuses on Feb. 20 and the South Carolina primary on Feb. 27., the question has become whether or not there really exists a racial barrier, or a discernible philosophical barrier, when it comes to Sanders drawing away the early support that Clinton has enjoyed in larger, more demographically diverse states."
http://www.commondreams.org/news/2016/02/14/sanders-surge-eyes-nevada-and-south-carolina-clinton-firewalls-show-cracks