 The Migration Division (known as the "Commonwealth Office"), also part of Puerto Rico's Department of Labor, was created in 1948, and by the end of the 1950s, was operating in 115 cities and towns stateside.The strength of stateside Puerto Rican identity is fueled by a number of factors.These include the large circular migration between the island and the mainland United States, a long tradition of the government of Puerto Rico promoting its ties to those stateside, the continuing existence of racial-ethnic prejudice and discrimination in the United States, and high residential and school segregation.