I ran across a few Afro-Mexican people in Tlacotalpan, in Veracruz. In fact, one man made a point of telling me this. I don't know what % of residents would identify themselves that way.
I rarely see African-American tourists in Mexico, but I no longer visit the most popular tourist places like Cancun or Cabo San Lucas.
I was just in Cartagena Colombia for Christmas, that's a place that has a wide blend of colors, and an African-American wouldn't stand out, at least based on color. Though I know little about the Colombian culture and whether there's racism there or not.
