Rising housing costs are putting a major squeeze on Americans.

Nearly 39 million households can't afford their housing, according to the annual State of the Nation's Housing Report from Harvard's Joint Center for Housing Studies.

Experts generally advise budgeting about 30% of monthly income for rent or mortgage costs.

But millions of Americans are far exceeding that guideline.

One-third of households in 2015 were "cost burdened," meaning they spend 30% or more of their incomes to cover housing costs. Of that group, nearly 19 million are paying more than 50% of their income to cover their housing needs.

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When so much of your paycheck is going toward keeping a roof over your head, it forces sacrifices in other budget areas, including food, health care and transportation.

"It depends on household type: Families with kids ... they cut back pretty severely on food," said Jennifer Molinsky, a senior research associate at the center. "Older adults cut back a lot on health care."

In 2015, there were almost 25 million children living in cost-burdened households.

Low-income families with children that are paying more than half their incomes to cover housing cut back the most on food, according to the report. They spend less than $300 a month, compared to households with no cost burdens, which spend about $500.

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"To make ends meet, these families often do not buy enough food for their households or they substitute cheaper but less nutritious foods, either of which can jeopardize their children's health and development," the report stated.

Low-income households are also more likely to compromise on the quality of housing, including living in places with structural issues.

Low housing inventory levels have helped push up home prices as many markets struggle with a supply and demand imbalance. Bidding wars are common in some places.

Home prices fell off a cliff after the 2007 housing crash, but they have been rising and last year surpassed their pre-recession peak.

That price appreciation has scared away many wanna-be buyers, who have been forced to rent. Demand for rental units has increased and pushed up prices.

As a result, the report found, more than 11 million renter households pay more than half their income on housing -- a 3.7 million increase from 2001.

Miami has the highest percentage of cost-burdened renters, at nearly 62%, followed by Los Angeles and Deltona-Daytona Beach, Florida at 57%.