Two years ago Salvador Rodriguez was retired from his job with one of Mexico's big banks. A few days later he went to the government office managing a pension scheme to which he had been contributing for nearly 30 years.

He was shocked to find that his lump sum payment amounted to less than the price of a new refrigerator. 'What was the point of putting all that money in,' he asked bitterly, 'it might as well have been stolen.'