MEXICO CITY – The number of Mexicans leaving their country – almost all for the United States – has reached 400,000 per year and will continue to grow for several more years, the head of Mexico's National Population Council said on Friday. The increase in migration has coincided with the United States increasing security on its southern border. "The effort to increase control of the (U.S.) border has not reduced migratory flows one little bit," Council Secretary General Elena Zuniga said. "After 15 years, what we have seen is a growth in migration, and growth in a way that is...