Complex sentence: Other ethnicities in the USSR also suffered similar discrimination and cleansing to that of the Crimean Tatars: between 1917 and 1933, half the Crimean Tatar population had been killed, deported or escaped to other countries.
Split into simpler sentences: Other ethnicities in the USSR also suffered similar discrimination and cleansing to that of the Crimean Tatars. Between 1917 and 1933, half the Crimean Tatar population had been killed, deported or escaped to other countries.