Kazakhstan
According to the 2009 Census data, there are very few Christians outside the Slavic and Germanic ethnic groups:
Czechoslovak–Hungarian population exchange
"We have decided now that our liberated State shall be a national state, rid of all hostile elements, living in brotherly harmony with the family of Slav States and in friendship with all peace-loving nations of the world. (§ 9) [...] The Czechoslovak Republic is a unitary State of two Slav nations possessing equal rights, the Czechs and the Slovaks." (Article II/1 )"