majority were Slavs, with a substantial minority of Finnic and Germanic peoples. Turkic peoples form a large minority, and are spread around pockets across the vast nation. Various distinct ethnic groups also inhabit the North Caucasus. Other minorities include Mongolian peoples (Buryats and Kalmyks), the Indigenous peoples of Siberia, a historical Jewish population, and the Koryo-saram (including Sakhalin Koreans). According to the United Nations, Russia's immigrant population is the third-largest in the world, numbering over 11.6 million in 2016; most of which are from post-Soviet states, mainly Ukrainians. There are 22 republics in Russia, who have their own ethnicities, cultures, and languages. In 12 of them in 2021, ethnic Russians constitute a minority: Languages Russian is the official and the predominantly spoken language in Russia. It is the most spoken native language in Europe, the most geographically widespread language of Eurasia, as well as the world's most widely spoken Slavic language. Russian is the second-most used language on the Internet after English, and is one of two official languages aboard the International Space Station, as well as one of the six official languages of the United Nations. Russia is a multilingual nation; approximately 100–150 minority languages are spoken across the country. According to the Russian Census of 2002, 142.6 million across the country spoke Russian, 5.3 million spoke Tatar, and 1.8 million spoke Ukrainian. The constitution allows the country's individual republics the right to establish their own state languages in addition to Russian, as well as guarantee its citizens the right to preserve their native language and to create conditions for its study and development. However, various experts have claimed Russia's linguistic diversity is rapidly declining. Religion Russia is a secular state by constitution, and its largest religion is Christianity. It has the world's largest Orthodox population. As of a different sociological surveys on religious adherence; between 41% to over 80% of the total population of Russia adhere to the Russian Orthodox Church. Other branches of Christianity present in Russia include Catholicism (approx. 1%), Baptists, Pentecostals, Lutherans and other Protestant churches (together totalling about 0.5% of the population) and Old Believers. There is some presence of Judaism, Buddhism, and Hinduism; pagan beliefs are also present to some extent in remote areas, sometimes syncretized with one of the mainstream religions. In 2017, a survey made by the Pew Research Center showed that 73% of Russians declared themselves as Christians—out of which