This panorama is more severe if we take into consideration that, between 1980 and 2000 the three cities were joined by other six, whose population surpassed one million inhabitants; the relative contribution of these new six cities represented 12.3 percent of the total of urban population; linked to this, the number of cities with between 500000 and one million inhabitants changed from four in 1980 to 190 in 200, and their relative weight, from 2.9 to 19.2 percent of the total urban population.
La contribución relativa de estas nuevas seis ciudades representó 12.3 por ciento del total de la población urbana. Aunado a esto, el número de ciudades de entre 500 000 y un millón de habitantes pasó de cuatro en 1980 a 19 en 2000, y su peso relativo, de 2.9 a 19.2 por ciento de la población urbana total.