Mexico's declining migration patters
...While the story suggest that the economy in the US is the main reason, I think the more aggressive immigration enforcement in the work place also was a factor. The economy has had its ups and downs in the past without effecting the immigration pattern. The early 1980s is a good example. What was different this time was an attempt to enforce immigration laws.
For the first time in a generation, since officials began to tally accurate records, the Mexican government reports a dramatic, sustained decline in the number of Mexican migrants going to the United States. The most recent count found that 186,000 fewer Mexicans left for other countries in 2008, compared with the previous year, a precipitous 22 percent drop, according to the National Institute of Statistics and Geography.