Can America's working families afford to have kids?

Many American families are under unprecedented financial pressure, but one type of family may be struggling more than others.

Families with small children are facing a sharp rise in the cost of child care, with prices for day care climbing at twice the rate of inflation since the U.S. left the recession in 2009, The Wall Street Journal reports, citing data from the Labor Department. American families with two children in day care pay an average of $18,000 annually, exceeding the $17,000 average annual expense for housing, according to Care.com.

At the same time, many families are contending with stagnant or even declining wages, which is placing even more stress on already strained household budgets. In 33 states and the District of Columbia, child care costs more than college tuition, while day care costs more than rent in most American cities, the Economic Policy Institute found in a 2015 report.

That's pushing many families to make tough choices when it comes to work, forcing them to rely on friends and families to help out or to cobble together staggered work schedules.

The cost of child care and nursery school has increased at least 2.1 percent per year since 2009, according to data provided by the Bureau of Labor Statistics. Last year saw the biggest increase, at 4 percent. By comparison, consumer prices rose less than 1 percent in 2015.

It may seem like a head-scratcher that child care is so expensive, given that child care workers earn notoriously low wages. Even dog trainers earn more than child care workers, who take home median pay of $10.60 an hour, according to the University of California at Berkeley's Center for the Study of Child Care Employment.

Child care costs so much partly because it requires a high ratio of personnel to students, especially when it comes to the youngest children. Then there's the rising cost of rents across the country, which is also leading day care centers to raise rates.

The issue has come up in the presidential race, with Democratic candidate Hillary Clinton proposing to cap day care costs at no more than 10 percent of a household's income, or what the Department of Health and Human Services defines as the affordability threshold for families. Expensive child care costs "severely squeeze working families and act as a disincentive for parents to stay in the workforce," Clinton's campaign said.

Republican candidate Donald Trump hasn't made child care proposals, according to the Journal. In November, he suggested that companies should provide day care for employees' children, saying it's "very easily" done.

"If we capped child care costs for families at 10 percent of their income, families across the nation would see significant and much-needed savings," wrote EPI economist Elise Gould in a May blog post about the cap proposal. "For families with one infant, the savings could range from $350 a year in Mississippi to over $8,304 a year in Massachusetts."

Families are cutting back on spending and changing their commitment to the workforce in order to handle child care. Care.com found that almost two-thirds said they paid more than they expected for child care, while 69 percent said child care costs have influenced their career decisions.