I've found the old census data from 1926 and decided to give them a new life by comparing to the newest census.
I haven't included all ethnic minorities in Russia as there're some mistakes in the old censuses, I've checked all censuses between 1926 and 2010, some ethnic groups're in a few first censuses then they just disappeared and appeared again. Of course it made me crazy but life is like this. As a result of this predictable problem with the old censuses, I decide to use in my visualization only the biggest ethnic groups.
Russians were the biggest ethnic group so I started numbering ranks from 2.
BTW please remember that the data are from census so only Russian citizens are included, foreigners staying on visas aren't part of the research.
My friend pointed out that the number of people who declare belonging to an ethnic group depends on a situation in the country, he gave me an example from the South America but I forgot the name of the country lol.