Over the 19th century, the Russian authorities encouraged the colonization of Bessarabia by Russians, Ukrainians, Germans(Bessarabian Germans), Bulgarians(Bessarabian Bulgarians), Poles(Poles in Moldova), and Gagauzes, primarily in the northern and southern areas vacated by Turks and Nogai Tatar, the latter having been expelled in the 1770s and 1780s, during Russo-Turkish Wars; the inclusion of the province in the Pale of Settlement also allowed the immigration of more Jews. The Romanian proportion of the population decreased from an estimated 86% in 1816, to around 52% in 1905. During this time there were anti-Semitic riots, leading to an exodus of thousands of Jews to the United States.