In 1990 the Mexico City metropolitan area, which includes the Federal District and 27 adjoining urban boroughs of the State of Mexico, had 15 million inhabitants; that is, 18.4% of the country's population.

In 1970 it had 9 million inhabitants, and in 1980 14 million. Thus, during the 70’s the city grew by 4.5% each year, but by only 0.7% each year during the 80’s.

This vigorous growth was a result of the dynamic social and economic environment which prevailed in the post-war era. Mexico's relative isolation in matters of international trade forced local manufacturers to concentrate on the internal market and, in particular, on the country's main center of consumption: Mexico City. This propitiated the creation of an important infrastructure whereby all the major routes of communication converged on the City. The centralist attitude of the government also played an important role in this inward development.

Consequently, the demographic growth of Mexico City was accelerated, together with the development of services and manufacturing industries to provide employment for this burgeoning population.

It is estimated that in 1995 Mexico City had 15.5 million inhabitants.

As can be noted, the City has reduced its annual rate of population growth to a level below both the national annual rate (2%), and the overall urban rate of growth (3.7%). It is, therefore, now the metropolitan area with the lowest rate of population growth in the country.

This is due, primarily, to a change in the distribution of the economic life of the country, which has experienced an important decentralization. Fundamental to this change has been the opening of the national economy to foreign commercial transactions. In particular the need to export, together with increased levels of foreign investment in the country, have determined the new location of production facilities and of business in general. This will eventually result in a redistribution of population in search of employment and higher levels of income.

Due to the expense involved for any business which establishes itself in this City, as well as the human and physical infrastructure which it offers, the City has become the center, above all, for the corporate headquarters of large, innovative, high-technology companies and businesses, and is also the financial hub of the country.

Thus, it is clear that the rate of growth of the City will gradually decrease and, if current tendencies persist, it is highly unlikely that it will reach a level of 20 million inhabitants in the short term, as was once thought, at least in the area made up of the Federal District and the adjoining urban boroughs.