Gross and inaccurate generalization. Not one caucasian or asian was there in 1980? Precise 4 to 1 relative statistics of black to hispanic? Not likely!
They don’t count freeway traffic.
While I do take those figures as being approximations, I don't doubt that they're reasonably close ones.
Given the area, the combined number of Caucasian and Asian residents probably amounts to little more than a rounding error in statistical terms.