The mandatory pension plan in Mexico is, as of today, a Defined Contribution (DC) type. This plan was formally introduced in 1997; before this, the mandatory pension plan was a Defined Benefit (DB) type on a PAY-AS-YOU-GO basis. Workers who entered this mandatory pension plan after July 1, 1997 had to join the new plan. On the other hand, workers who were already in the labour market before that date could choose between either of the plans to retire.