Finding affordable housing was a problem for about three in 10 Canadians between 2002 and 2004, according to a study by the Canada Mortgage and Housing Corporation and Statistics Canada.

The study, released Friday, said that during the three-year period 28 per cent of Canadians reported spending at some point more than 30 per cent of their household income on shelter. Thirty per cent is commonly held as the upper limit benchmark in shelter cost-to-income ratio.

"While a stable 20 per cent of Canadians live in households spending above the affordability benchmark for shelter in any single year, when measured over a three-year period, 28 per cent reported living in a household ever exceeding the benchmark-12 per cent for one year, seven per cent for two years and nine per cent for all three years," the study said.

People in Vancouver were identified as the most likely in the country to exceed the affordability standard, with 44 per cent of residents reporting doing so at least once during the three-year time frame.

The report also found that lower-income families were most likely to exceed the affordability benchmark, owing to low-paying jobs, unemployment, and family breakups, the federal agencies said. Renters, people who live on their own, single mothers and recent immigrants were also identified as spending more on housing.

People undergoing major life transitions — such as becoming a homeowner, getting married or divorced — also reported surpassing the affordable income-shelter ratio, the study said.