The population at the time of annexation was 74% ethnic Russian 2% Ukrainians and the rest Tatar. Of 500,000 Tatars 200,000+ fled either to Kiev the West, Turkey or elsewhere due to a process of ethnic cleansing. In that time another 500,000 Russians moved to Crimea. Overall it's population should be slightly above 2 million with maybe 200-300k Tatars.