However, their coverage increases with age. In contrast, coverage is relatively constant across age groups in mandatory or quasi-mandatory private pension plans, as Australia and the Netherlands illustrate. Among the poorest income groups, however, voluntary scheme coverage is quite low - around 15% - except in the United States where it reaches 29%. By contrast, the mandatory/quasi-mandatory systems of Australia and the Netherlands plateau out much earlier - after the 2nd or 3rd deciles - and coverage of the poorest income groups exceeds 65%.