A guest worker program allows foreign workers to temporarily reside and work in a host country until a next round of workers is readily available to switch. Guest workers typically perform low or semi-skilled agricultural, industrial, or domestic labor in countries with workforce shortages, and they return home once their contract has expired. While migrant workers may move within a country to find labor, guest worker programs employ workers from areas outside of the host country. Guest workers are not considered permanent immigrants due to the temporary nature of their contracts. In the United States, there have been efforts at guest worker programs for many years. These include the Bracero Program, enacted during World War II; attempts by the George W. Bush administration; and the current H-2A and H-2B visa programs. However, attempts at improving the programs have been ongoing and have been vigorously debated. While the United States' guest worker programs do not explicitly focus on any specific nationality, such plans typically target labor from Mexico, due to the shared border, the economic disparity, and the history of programs between the countries. The Bracero Program was a temporary-worker importation agreement between the United States and Mexico from 1942 to 1964. Initially created in 1942 as an emergency procedure to alleviate wartime labor shortages, the program actually lasted until 1964, bringing approximately 4.5 million legal Mexican workers into the United States during its lifespan. The Bracero Program expanded during the early 1950s, admitting more than 400,000 Mexican workers for temporary employment per year until 1959 when numbers began a steady decline. While illegal immigration was a concern of both the United States and Mexico, the Bracero Program was seen as a partial solution to the upsurge of undocumented worker entries. Under the program, total farm employment skyrocketed, domestic farm worker employment decreased, and the farm wage rate decreased.