The largest number of Americans outside the United States live in Mexico. According to American Citizens Abroad, there are more than 1,000,000 Americans living in the Mexican Republic (as of 1999).[10] However, this number is disputed. Some estimates set the number as low as 124, 082. According to the 2000 census, there were 343,591 Americans living in Mexico. Mostly, people who come from the USA are students, retirees, or missionaries, pastors, and other employees from religious organizations. Also, professors who come employed from Mexican companies to teach English, as well as some corporate employees and executives. These residents often don't stay the whole year, with many retirees living half of the year in the USA to keep their retiree benefits, while others, known as "snowbirds", spend only the winter months south of the border. The American community in Mexico is found throughout the country, but there are significant concentrations of U.S. citizens in all the north of Mexico, especially in Tijuana, Mexicali, Los Cabos, San Carlos, Mazatlán, Saltillo, Monterrey and Nuevo Laredo. Also in the central parts of the country such as San Miguel de Allende, Ajijic, Chapala, Mexico City and Cuernavaca, and along the Pacific coast, most especially in the greater Puerto Vallarta area. In the past few years, a growing American community has developed in Mérida.