In 2020's presidential election, it was shown that Joe Biden lost support from nonwhite voters, most of whom were ideologically conservative.
However, he not only still won this voting group, but he did better here than Kerry. Since 16 years is a fairly long time for demographic changes, I am wondering if there was a correlation between these two variables at the county level: the increase in minority population from 2000 to 2019 (the most recent data available now, and 2000 is a census year) and the change in two-party Democratic vote share, from 2004 to 2020 on the presidential level.
Notes: I am asking this question because I want statistical analysis for a project I am working on, and want to see how demographic change affected real-life election results, and not just projections. As an example, the coordinate for the national average is (10, 3.5) -- which means a 10 percentage point increase in nonwhite population in the US as a whole, and a 3.5 percentage point increase in Democratic vote share from 2000 to 2019.