It is not referring to a rise in radical Islam, but to the number of people within Russia’s borders who identify as Muslim. I too have read from an article by demographic researcher Marlene Laruelle who says that a conservative estimate would be that Muslims are on track to make up 1/3 of Russia’s population by 2050. And ‘alarmist’ estimates say 1/2.
This factors in citizens of Russia’s Islamic republics like Chechnya and Daghestan, but also the mass influx of Central Asian migrants from former USSR territories.
None of these estimates factor in things like Muslims who convert to Christianity, etc...
no difference in the end, all muslims will tow the perv prophets line when faced with beheading from sharia police