Rko1234 via Getty Images The cost of owning a single-family home in Canada is the highest on record.

As we close out 2018, the Royal Bank of Canada is leaving us with some unwelcome news: It's never been this expensive, relative to income, to own a detached home in Canada. RBC's latest housing affordability report showed it now takes 59.2 per cent of an average household's income to afford an average single-family home. That's the highest in records going back to the mid-1980s, and miles above the long-run average of 44.7 per cent.

RBC Economics Royal Bank of Canada's measure of housing affordability has reached its highest (worst) levels since 1990. For detached homes, the cost of ownership is at a record high.

For years, soaring house prices in many markets were behind the trend, but these days rising interest rates are "the main culprit" pushing home affordability out of reach, economists Craig Wright and Robert Hogue wrote. For the housing market overall, including condos, affordability deteriorated to its worst levels since 1990, with an average-earning household now having to spend 53.9 per cent of its income to afford an average home. That includes monthly mortgage payments, as well as property taxes and utilities. It assumes a 25-year mortgage with a five-year fixed rate and 25 per cent down. Watch: Canada's most expensive condo got a serious price cut. Story continues below.

"Are only the rich able to buy a home these days?" Wright and Hogue asked in the report. "That certainly looks like it in Canada's most expensive markets. Buyers in Vancouver, Toronto and Victoria needed between two and three times the median household income to qualify to purchase an average home." Earlier on HuffPost Canada: U.S. vs. Canadian Real Estate: Who Won And Who Lost?

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Canada's Housing Market Ranked Third-Riskiest In World But it's Montreal that has seen the fastest deterioration in home affordability, the RBC report showed. "The area has been one of the stronger markets in Canada in the past year — another being Ottawa — that saw solid price gains amplify the effect of higher interest rates on ownership costs." The economists noted that "despite some deterioration in the latest period, owning a home remains affordable in the majority of other markets in Canada." Stress test's major impact The report also showed the profound impact the new mortgage "stress tests" have had on the market, particularly in the priciest cities. In Vancouver, the stress test added almost $36,000 to the qualifying income needed to buy an average priced home. You now need a household income of $211,000 to buy an average home at $1.1 million. In Toronto, the stress test added $27,000 to the qualifying income for an average house, and households there need to earn $167,000 to afford an average home.

RBC Economics Income needed to buy a home.