In 2012, African-Americans comprised a record 13 percent of all voters. President Barack Obama was reelected with 93 percent of the African-American vote, leaving Gov. Mitt Romney with only 6 percent of the African-American vote. Obama is now campaigning against Trump, and hoping to keep his share of the African-American vote below the 11 percent that George W. Bush won in 2004 during the housing bubble.  

On Friday, a poll of 506 Pennsylvania voters by Harper Polling showed Trump has the support of 18.46 percent of African-Americans. That's eight points more than Romney's share of the national vote in 2012, and if it proves true during the ballot, that 18.46 percent African-American support translates into 2 point shift towards Trump. The poll also said another 4.6 percent were undecided. 

The Harper poll is small, with an error margin of 4.4 percent, but an Oct. 30 poll of 1,249 likely voters in Pennsylvania showed Trump has 19 percent support among African Americans, while another 7 percent remain undecided. That poll has a error margin of 2.77 percent.