SmartAsset, which recently unveiled its mortgage calculator for home buyers, set out to find out where the heaviest mortgage debt lies. It analyzed data on 3.5 million records from the Consumer Financial Protection Bureau’s Home Mortgage Disclosure Act database on home buyers’ average incomes and compared it to home buyers’ average mortgages. To create the list, SmartAsset divided the average mortgage by the average income in each metro area. This yielded the average mortgage-to-income ratio which we used to rank the areas.

Findings:● California leads the way in mortgage debt - On average, California residents take on the most debt relative to their income in order to buy their homes. In total, 17 of the 25 areas with the highest average mortgage-to-income ratio are in California. California has the second-highest median home value at $477,500, according to Census Bureau data and more expensive homes generally mean bigger mortgages. The home values in California’s most expensive metro areas are even higher. In San Francisco-Redwood City-South San Francisco, the average home buyer took out a loan of $932,700. In San Jose-Sunnyvale-Santa Clara, that number is $740,700.

● Midwest takes on the least debt - The metro areas where residents take on the least debt relative to their incomes tend to be located in the Midwest. Illinois, for example, has four metro areas in the bottom 10 and Indiana has two. There is a wide range between top 10 and bottom 10. The top 10 metro areas with the largest mortgage-to-income ratios had an average mortgage-to-income ratio of 3.44 and the bottom 10 had a mortgage-to-income ratio of 1.6.

● Wealthier residents take on more debt - Another pattern to emerge from this research is that richer residents take on more debt relative to their income, on average. The average income for homebuyers across the 10 cities with the highest mortgage-to-income ratio was $165,572. That is about $100,000 more than the average income for the bottom 10 cities.

● Low property taxes - The states that comprise the top 25 places in our study (California, thanks to Proposition 13, Colorado, Utah and Hawaii) all have below-average effective property tax rates, meaning homeowners are paying a lower percentage of their home’s value in property taxes. Illinois has the second-highest property taxes in the country and is the most common state found at the bottom of the rankings.