CNN

A man votes in Wilmington, North Carolina.

(CNN) – It’s the mirror image of Barack Obama’s white working class voter problem – Hillary Clinton’s continuing troubles with black Democrats.

Obama pulled in 78 percent of the black vote in South Carolina’s January contest, 84 percent in Missouri’s February vote, 87 percent in Ohio’s March 4 primary and 90 percent in Pennsylvania last month.

Tuesday night, he pulled in 91 percent of North Carolina’s black primary voters, and 92 percent of Indiana’s, according to early exit polls – numbers that would pose a major challenge for any Democratic White House hopeful.