OTTAWA - About one out of every six families with children in the Toronto region is headed by just one parent, according to new census information that shows the continued decline of the so-called nuclear family across Canada.

The latest data from the 2006 census, released Wednesday by Statistics Canada, indicates 16.9 per cent of all families in what's known as the census metropolitan area of Toronto have just one parent and among those families with children, the percentage climbs to 24.0 per cent.

When it comes to who heads up families with just one parent, women by far outnumber the men. Among the lone-parent families in the Toronto region, 83.2 per cent are headed by females.

The proportion of lone-parent families in the Toronto region has increased since the 2001 census, when they represented 16.4 per cent of all families and 21.3 per cent of families with children.

Statistics Canada defines a lone-parent family as a family headed by an adult who is single, separated, divorced or widowed. It could also be a grandparent who is raising a grandchild when the child's parent isn't in the home for whatever reason.

Lone-parent families made up less than 10 per cent of the Canadian family structure during the early years of the baby boom in the 1950s and '60s. But that trend has been going the other way over the last 40 years to the point now that there are more families with just one parent than ever before.

Nationally, lone-parent families make up 15.9 per cent of all Canadian families and 25.8 per cent of those families with children. Alberta has the lowest percentage of lone-family parents among all the provinces (14.4 per cent), while Nunavut has the highest (27.6 per cent).

The traditional "nuclear" family -- married couples with children -- make up 50.5 per cent of all families in the Toronto region. That's a decrease from the 2001 census, when it was 51.0 per cent.

Common-law couples with children have increased over the last five years, from 12.8 per cent to 14.6 per cent.

Across Canada, beyond the lone-parent families, the rest of the family units break down like this: married with children (38.7 per cent); common-law with children (6.9 per cent).

In Ontario, the census shows that 44.5 per cent of families were married couples with children and 4.1 per cent were common-law-couples with children.

The census also breaks out same-sex couples _ and the 2006 census was the first to measure same-sex married couples. In Canada, there were 7,465 same sex married couples and 37,885 same-sex common law couples.

In the Toronto region, the census indicated there were 2,390 same-sex married couples and 7,230 common-law couples of the same sex.

Divorced people make up 6.1 per cent of the population in Toronto, while 33.1 per cent have never married.

For the last 25 years, there has been a steady increase in the number of Canadians who have never married. Nationally, 34.9 per cent of the population has never been married and 8.0 per cent are divorced.

The census is conducted every five years by Statistics Canada and is based on information filled out by Canadians on May 16, 2006. The data released Wednesday on families follows information released earlier this year on overall population growth, as well as a look at the age and sex breakdowns of the population.

Future census information to be released by Statistics Canada over the coming months will give demographic breakdowns of a variety of topics, including language, immigration, labour force activity and education.

Census metropolitan areas do not conform to established municipal boundaries. Statistics Canada determines its own geographic definition of a metropolitan area with a population of at least 100,000, but it also includes surrounding urban and rural communities based on analysis of commuting patterns and other factors. Looking at metropolitan areas this way takes in to account the growing impact of suburban areas on Canada's largest cities.