Sweden has experienced three periods of labor immigration since 1945. The first from 1945-1971 saw high- and low-skilled migrants due to transferable and non-transferable skills. The second from 1994 onward included more EU members and expansion. This mainly continued the first period's skill pattern. The third period since 2008 requires a job offer and minimum monthly income for a work and temporary residence permit, with wages and conditions set in collective agreements. Obtaining permanent residence takes four of five years of work (now seven years). However, high minimum wages have reduced demand for low-skilled foreign workers while temporary agricultural workers face difficult conditions.