In these types of systems, each worker accumulates pension contributions to finance her or his retirement benefits. While specific design features varied substantially across reforming countries - for instance, regarding the relative size of the private pillar (i.e., the share of mandatory wage contributions that were directed to it) - the overall trend was towards a stronger link between contributions and benefits. First, benefit levels in individual accounts are directly based on past contributions and therefore the benefit each one can obtain more closely reflects working, earning and (especially) contributory histories.