Belarusian was designated the official state language. In 1995, after a national referendum on the subject, Russian also was elevated to a state language. Belarusian and Russian, along with Ukrainian, form the eastern branch of the Slavic languages of the Indo-European language family. More than 90 percent of the population has native fluency in Russian, which was promoted by the state during the Soviet period. Belarusian is commonly spoken in rural areas, but in urban centers it is rarely heard.