“Muslims are at least 10% of the Russian population. Russia is doomed.”
Russia’s moslem population was 11 percent in the 1897 census.
https://en.wikipedia.org/wiki/Russian_Empire_census
They most recent estimate for moslems is 6.5 percent.
https://en.wikipedia.org/wiki/Religion_in_Russia
Contrast that with the countries of the West, who have only had moslems present since the mid 1960s, and they are on the verge of dominance in many countries.
That is not the most recent estimate. It is 10% according to the 2017 estimate. 2017 is more recent than 2012.
The Russians estimate that there are 1.5 million Muslims in Moscow alone.
The decay of Muslim population in Russia is caused by the disintegration of Soviet Union.
Most formerly Soviet Muslims are now in independent nations of Azerbaijan, Kazakhstan, Uzbekistan, Kirgizstan, Tajikistan and Turkmenistan. All those countries are now Muslim majority and guess what, the Christians there are persecuted!
Many Christians (and Jews!) from these states left for Russia and other places.
That made the rest of Russia proportionally less Muslim than previously, but that may change too!