In the February 1946 census, 2,288,000 persons were listed as Germans and 417,400 became subject to verification aiming at the establishment of nationality.[16][17] From the spring of 1946 the expulsions gradually became better organised, affecting the remaining German population.[3] By 1950, 3,155,000 German civilians had been expelled and 1,043,550 were naturalised as Polish citizens.[18] Germans considered "indispensable" for the Polish economy were retained; virtually all had left by 1960.