The growth of Canada's labour force will slow to a crawl over the next two decades as an increasing number of baby boomers leave their working days behind, according to a projection by Statistics Canada.

In an analysis released Wednesday, the statistics agency says the national labour force had an annual growth rate of about 1.4 per cent from 2006 to 2010.

But it expects labour expansion to drop to a rate of just 1 per cent by 2016, as more and more boomers retire, falling to a level between 0.2 per cent and 0.7 per cent from 2021 to 2026.

StatsCan says there will be a corresponding drop in overall workforce participation from a rate of 67 per cent in 2010, to somewhere between 59.7 per cent and 62.6 per cent over the next 20 years.

With the oldest boomers already in their early- and mid-sixties, StatsCan says the number of seniors in Canada is rapidly increasing while the labour force is getting older.

Ten years ago, only 10 per cent of active workers were age 55 or older. By 2009, this group made up 17 per cent of the labour force. Projections suggest they will account for roughly one in four Canadian workers by 2021.

While StatsCan believes there will be a greater number of baby boomers working past the age of 65, there will also be a smaller proportion of younger people working to support them in their golden years.

By 2031, there will be fewer than three people in the labour force for every retired person, a ratio that has declined sharply over the baby boomers' collective lifetime.

According to StatsCan, there were roughly six people working for every person who was retired in 1981, at a time when the youngest boomers were still making their way through high school and university.

Canada's workforce will also become much more diverse as the baby boomers retire.

StatsCan says that about one-third of the labour force could be foreign born by 2031, extending long-running trends in employment diversity and immigration to Canada.

In 1991, fewer than one in five Canadian workers was born outside the country and only 10 per cent belonged to a visible minority group. Fifteen years later, 21.5 per cent of the labour force was foreign born and 15 per cent of workers belonged to a visible minority group. StatsCan expects these numbers to jump to 32 per cent and 23 per cent, respectively, by 2031.

With files from The Canadian Press