Portuguese immigration, from Atlantic islands including the Azores, Madeira and the Cape Verde Islands, began in the 19th century to provide labour for the nascent agricultural industry. From the beginning, Portuguese labourers, who have emigrated under special agreements, have not been allowed to do so on the basis of permanent immigration. They were expected to return to their homelands after a fixed period. Some were able to stay, however and by the 1940s there was a sizeable number Portuguese-Bermudians who were legally Bermudian (and British by citizenship). Until the recession of the 1990s, however, Bermuda continued to rely on large-scale immigration of temporary Portuguese workers who laboured at jobs Bermudians considered unworthy (notably, anything to do with agriculture or horticulture). Many of these immigrants lived and worked in Bermuda for decades on repeatedly renewed work permits, without gaining the right to permanent residence, British citizenship, or Bermudian status. When work permits were not renewed, especially during the recession, many were forced to return to the Azores, often with full-grown children who had been born and brought up in Bermuda. Although the numbers of Portuguese "guest workers" has not returned to its former levels, the number of Bermudians today described as "Portuguese" (often considered a distinct racial group from Whites of Northern European ancestry, and historically stigmatised by all other Bermudians) is usually given as ten percent of the population. This number does not include many Black Bermudians with White Portuguese ancestry, and obscures also that some of the Portuguese immigrants were Blacks from the Cape Verde Islands. The actual percentage of Bermudians with Portuguese ancestry is likely far larger.