Bivariate Map

Bivariate
Instead of a typical U.S. map, I found a bivariate choropleth calculating 2002 population density & % population change from 1989-2002 of Russia's central federal district.  The highest pop. density is in the center-north and the southern regions.  The same goes for the % pop. change.  I wonder what the trend is (must be around Moscow or St. Petersburg)...