Before 1945 under the Japanese occupation, the Taiwan economy was developed to export sugar, rice, salt and other primary products in exchange for Japanese manufactured goods and fertilizers. The island, which suffered severe losses from allied air bombings during the war, was returned to the Republic of China late in 1945. Rehabilitation was slow in the early post-war years owing mainly to difficulties in replacing or repairing damaged plant and to the shortage of fertilizers indispensable to the production of rice and sugar. Since late 1949, when the National Government of the Republic of China removed to the island, development has been facilitated by the influx of technical personnel and capital equipment from the mainland and by economic aid from the United States Government.