As a news reporter for many years in the racially diverse and sensitive states of New Jersey and Ohio, one's racial composition was sometimes a practical matter in story composition. Race would turn up in topics such as entertainment, crime, school/government policy, and politics and always required accuracy and careful consideration.
"Negro" and "colored" were no longer acceptable usages for African-American references in this '80s-'90s timeframe, nor was "mulatto" acceptable usage to describe people - like 1980 Miss America winner Vanessa Williams - who were half-black and half-white.
Williams and others of "mixed" racial background were referred to as such, followed by a descriptive phrase of the recipe. "Bi-racial" came into wider usage during this time, mostly to describe people who were equal parts white and black, and usually because the subject had parents who were clearly one of each.
If one's racial heritage was something other than black and white, the more likely referance was "mixed."
But "mixed" could also be used to describe people of more than than two racial backgrounds, and proportions other than 50/50.