Canadians are having fewer babies and living longer, which means the population is getting older, Statistics Canada reported Friday.
As of July 1, the median age of Canadians was 39.5 years, up 0.2 years from the same date in 2008, and 3.1 years higher than in 1999.
The agency said projections indicate that the median age could reach 44 years during the 2030s.
While fertility rates remain below replacement level, life spans are increasing.
As of July 1, there were almost 1.3 million people aged 80 and over in the population. Of those, an estimated 6,000 were 100 or older.
In 2001, the earliest year for which population estimates of centenarians are available, they numbered 3,400.
By the 2030s, there could be 15,000 people at or above the century mark.
The report said Canada's youngest population was in Nunavut, where the median age in July was 24.2 years and where children under 15 made up almost a third of the population.
Among the provinces, Alberta had the lowest median age at 35.6 years and Newfoundland and Labrador, at 42.0 years, had the highest median.
The working-age population, people between 15 and 64, is also getting older. As of July 1, the median age of this group was 40.5 years, up from 38.4 years in 1999.
The baby boomers, the largest population bulge in the country's history, are now part of the 45 to 64 age group.
They accounted for 40.4 per cent of the working-age population. In 1999, about a third of the working-age population was between 45 and 64.
Between 1999 and 2009, the proportion of people 30 to 44 within the working-age population fell to 30.1 per cent from 36.6 per cent.
Baby boomers will soon leave the workforce
The report says by 2011, baby boomers will progressively start to leave the working population.
The effects of the baby boom and the subsequent baby bust suggest the size of this group will continue to shrink.
As of July, the working-age population accounted for 69.5 per cent of the population, but this could slip to 62 per cent by the 2030s.
However, Canada still has one of the lowest proportions of seniors among the OECD countries. As of July 1, seniors 65 and over accounted for a record high 13.9 per cent of the population, while children under 15 constituted 16.6 per cent.
In the OECD, the average population of seniors is 14.3 per cent.
But the Canadian baby boomers are set to push the senior population to a quarter of the total within 20 years.