In the 2012 election, 73% of Asian-Americans voted democrat.
Again - that’s very different than 90-97%.
Just what are we counting as a “demographic”? For instance, African-Americans have a very high support for Democrats, but I expect that African-American women would be even higher. Or homosexual African-American women, or young homosexual African-American women, and so on. Eventually, if you overlap enough demographics and slice them finely enough, you can get a “demographic” of a single person, who supports a particular party 100%.
92.8% percent of South African Whites vote for the Democratic Alliance in the 2014 elections.