It’s generally understood that rising housing costs, and a shortage of new units, have contributed to an affordable housing crisis in the United States. New research by economists at Apartment List have found that inequality has also been rising, with those struggling to afford rent tending to pay a much greater share of their income than wealthier Americans.

Overall, the bottom 10 percent of the income distribution has seen the steepest rise in costs since 1980, while the top 25 percent of earners have actually see a decline in housing costs. Renters, at all income levels, are spending a great share of their income on rent than they did in 1980, while homeowners are paying a smaller fraction of their monthly paycheck for housing.

This phenomenon isn’t limited to pricy big cities or part of coastal California. Researcher Igor Popov found that housing for the bottom half of income distribution grew more than those on the top half in every single one of the top 100 metro areas across the U.S. In 45 of the 50 largest U.S. cities, income inequality grew.

One of the main drivers for this increasing disparity is the similarity in rent and housing costs along large stretches of the income divide. Put another way, lower- and middle-income Americans tend to have similar housing costs, despite varying paychecks, exacerbating the financial stress on low-income Americans and highlighting the human cost of our affordable housing shortage.

Apartment List researchers found that those in the lowest quartile of income make 27 percent of the median household, yet they still need to pay 79 percent of what the median household pays in rent. Despite making a fraction of the income, they still have a somewhat similar housing burden.

Two large trends are at play. In the rental market, an influx of high-end rental properties, feeding an increased population of high-end renters, has contributed to higher costs, especially in supply-constrained cities. The median renter pays 23 percent more than he or she did in 1980. At the same time, for homeowners, lower mortgage rates and the ability to refinance have countered the rise in prices, leading to a relative decrease in their monthly mortgage payment.

Again, this income is widespread. Median homeowner income is higher than that of the median renter in every one of the top 100 U.S. metros, and double that of renters in 55 markets. The advantage gained by homeowners, from mortgage-interest tax deductions to refinancing, is exacerbating the housing divide.

See the graphs and read the rest of the article at Curbed