If you are looking for official numbers on expats in Mexico, make sure you look at a number of sources.
How many expats really live in Mexico?
It is difficult to say, because there are many expats flying "under the radar" that are living and working in Mexico on tourist visas. There are also a number of foreigners that own property in Mexico, but do not live in the country full time. It is expected that 5 million Americans will call Mexico home by 2025 as people look for low cost areas to retire migrate to Mexico
1. Americans (Mexico has the largest population of Americans abroad) - estimated anywhere from 200,000 (highly unlikely!) to around 2 million
2. Canadians - 1.4 million
3. Spaniards - around 700,000
After the financial crisis of 2004 in Argentina, Mexico saw huge numbers of Argentineans flock to Mexico City. In fact, there are now areas of the city where most of the waiters/models are from Argentina.
Now, a funny video about "illegal immigration" to Mexico: