Low-income earners see little change in disposable income when they retire, while those earning more are likely to see a significant drop, Statistics Canada said Monday.

The numbers are important because with an aging population, the proportion of retirees will increase considerably and the financial stability of seniors will become more important.

On average, family disposable incomes at age 75, when most workers are retired, are 80 per cent of incomes at age 55, when most are working. But there are large variations within that average.

The study determined the extent to which Canadians at age 55 were able to maintain their family incomes as they moved into retirement until their mid-70s. It covered the period from 1983, when the people in the analysis were age 55, to 2004, when they reached age 76.

Among workers with average incomes at age 55, family disposable income fell after 60, declined until 68, then stabilized at about 80 per cent of the income level they had when they were 55.

Those with incomes in the bottom fifth of the population saw little change in income as they moved from age 55 through the retirement years, thanks mostly to the public pension system. These lower-income workers experienced high levels of individual income instability in their late 50s and early 60s, but after retirement their incomes became more stable.

At 75, they had average after-tax family income of about $30,000 for a family of two. About 60 per cent of it came from the public pension system.

However, better-off workers in the top fifth of earners saw substantial drops in income by the time they were 75. The richest workers at age 55 replaced on average about 70 per cent of their income during their 70s.

Still, these workers had an average family income of $90,000 after taxes for a family of two by the time they reached 75.

About 40 per cent of this income came from private pensions or Registered Retirement Savings Plans, 28 per cent from investment and capital gains, and about 18 per cent from public pensions.