The country's largest labor federation says the hourly wage in Mexico has fallen to one of the lowest in the world in the past six years. Mexicans who earned the equivalent of $1.90 an hour in 1982 now earn 40 cents an hour, the Mexican Labor Federation said. The minimum wage, last raised in March, is 8,000 pesos a day, or about $3.50. The federation said high payments on the foreign debt were draining the economy. It warned that the loss of buying power generates discontent and could endanger the stability of the country. A government anti-inflation program has brought the increase in consumer prices down from a monthly rate of 15.5 percent in January to 1.7 percent in July. Inflation in 1987 was a record 159.2 percent.