The population of Mexico is 122.2M *, with a birth rate of 19/1000 and a death rate of 4.9/1000. While Mexico’s population is not growing as rapidly as that of many other countries, the numbers still add up to far too many people trying to make a living in this largely arid country, with more being added every year. Although the national government does its best (most of the time) to support industry and commerce, it simply cannot keep up with population growth; it’s fighting a losing battle. Hence the flight of millions, illegally, into Arizona and other U.S. states. This flood will have no end until the U.S. effectively stops illegal immigration, or until Mexico takes steps to curb its population growth. Neither seems to be in prospect at the moment.
* Statistics from Wikipedia, accessed 29 April, 2010, and are current as of 2009.