Massive drop in teen pregnancy each year and small increase in married births some years.
Teen births still represent about 1 in 11 births for non-Hispanic black mothers, which has brought them in most recent full data to about 1 in 8 unmarried births. The very most recent couple years of data, including the preliminary stuff for 2016 show that the decline in unmarried childbearing has reached into the 20-24 age group.
As far as black birth goes, there’s still some room for teen births to continue their steep decline. The question after that is whether the increases in unwed childbearing among older mothers (25+) will keep the overall unwed birth percentage around 65% or whether they too will decline.