There was definitely a lower turnout among African-American voters.
I live in MO-1. The population, according to 2010 census, is roughly 50% black and 47% white. In the 2012 election, I have counted 351,065 votes cast for President; 79.87% of that for Obama, 18.89% for Romney, and 1.24% for others (Johnson and Goode). But in 2016, the number of votes cast, according to my count, is 320,454. That's a drop of 8.6%. Clinton got 76.81%, Trump got 18.76%, and 4.43% were for the others (Johnson, Stein, Castle, and write-ins). The drop in the number of votes cast for the Dems was almost 34,000; the drop in the number of votes cast for GOP was about 6,000; and the increase in the number of votes cast for others was about 10,000.
I have also calculated the presidential votes within each State Representative District, of which there are about 36 (wholly or partially within MO-1). Districts 67, 68, 73-79, and 84-86 are the districts that are predominantly black. Those 12 districts are adjacent to one another, and collectively that region is 70% black. That's where the vast majority of the decline in voter turnout occurred. I calculated that in 2012, those 12 districts cast almost 210,000 votes. But in 2016, the number declined to about 182,300 votes -- a drop of 13%. There was a decline in the white-majority State Representative Districts within MO-1 too, but no where near as drastic. State Rep Districts 75 and 76 have the highest percentages of black residents in the entire state, and those two had the worst decline in voter turnout.
This was not unique to the St. Louis area.
It was a national phenomenon.
