"Family" is essentially defined as being a household of at least two people.
"Statistics Canada defines a family as a couple — with our without children, married or common-law — or a lone parent with at least one child in the same house," the Canadian Press reports.
For the first time, there are now more one-person households than couple households with children, the Globe and Mail reports.
And while married couples are still the predominant family structure in Canada, their numbers only increased by 3.1 per cent since 2006, while the number of common-law couples rose by 13.9 per cent over that same period. Single-parent families rose by 8 per cent.
Canadian families: Then and now
The data, released on Wednesday by Statistics Canada, also reveals almost 20,000 more same-sex common-law and married couples in Canada — with 64,575 same-sex-couple families in Canada, up from 45,345— since Parliament approved same-sex marriage legislation in 2005.
[ More Census 2011: Compare community results on interactive map ]
The same-sex numbers spike isn't entirely accurate, however, as some same-sex roommates were incorrectly counted as couples. Statistics Canada admitted Wednesday that "it may have overestimated by as many as 4,500 the number of same-sex married couples in parts of the country," the Canadian Press reports.
One explanation for the error is traveling workers who are married to members of the opposite sex but end up living with same-sex roommates at their seasonal job locations.
"We seem to observe that in more transient communities where we have a lot of temporary workers coming in. So it could be people living together, for example, and reporting each other as married, but not necessarily to each other," said census manager Marc Hamel.
How census may have counted roommates as married gay couples
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For the first time, the census also collected data on both the number of foster children and the number of stepfamilies in the country.
"The fact that it's national data — data being collected through a national statistical organization — helps to bring focus on the question of foster care and foster children, at a national level," said Nico Trocme, director for McGill University's Centre for Research on Children and Families.
"Foster children are one of the most vulnerable groups in Canada. We need to be shining a light on them more often, rather than less. So I'm thrilled."
Last year, there were 29,590 foster children ages 14 and under living in Canadian households.
About one in eight couples with children is now considered a "blended family," or stepfamily. Just over 30,000 children aged 14 and under lived in skip-generation households in 2011, where grandparents were present and parents weren't. That number is up almost 20 per cent from a decade earlier.
"There are skip-generation families, intact families, simple step families, complex step families, opposite-sex families and same-sex families," the Canadian Press explains, reporting that this census went deeper than before in examining how stepfamilies and their households are set up.
[ Related: How the families of today differ from 1960s ]
Families themselves are getting smaller and not just because single-parent families are on the rise. In 1961, the average number of children per family was 2.7. That number is now just 1.9.
"One of the interesting things about a census is it gives Canadians an opportunity to see themselves across the country and to begin to see that they're not alone," Nora Spinks, CEO of the Vanier Institute of the Family, told CTV News. "And if they are going through some tough times like trying to navigate the complexities of a blended family or going through a divorce…knowing they're not alone is a really important piece of the census experience."
[ Related: Test your knowledge on how families are changing ]
The census also confirmed the existence of the "failure to launch" phenomenon, registering 42.3 per cent of young adults in their 20s — particularly men — still living with their parents.
Read the census's other family-related findings here.
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