In October 1961 an initial agreement was signed with the Turkish government and the first Gastarbeiter began to arrive. By 1966, some 1,300,000 foreign workers had been recruited mainly from Italy, Turkey, Spain, and Greece. By 1971, the number had reached 2.6 million workers. The initial plan was that single workers would come to Germany, would work for a limited number of years and then return home. The significant differences between wages in their home countries and in Germany led many workers to bring their families and to settle—at least until retirement—in Germany. That the German authorities took little notice of the radical changes that these shifts of population structure meant was the cause of considerable debate in later years.