Americans looking for an affordable, high-quality caregiver for their kids will be hard-pressed to find one in any U.S. state, according to one of the broadest studies of its kind.

Full-time care in a center for children ages 4 or younger costs more than average in-state college tuition, while an in-home caregiver costs 53 percent of U.S. median household income, according to a report Wednesday from New America, a Washington-based research organization.

The study used proprietary data from the online marketplace Care.com Inc., a survey of 15,000 households, and publicly available figures from the Census Bureau and Child Care Aware of America.

Quality as measured by accreditation and user reviews, and availability as measured by the ratio of child care workers to young children, is also inconsistent across the country; no state scores well across the board for cost, quality and availability, the report says.

The report expands on previous work by other groups by incorporating nanny-care cost data from Care.com's more than 8 million caregiver members, as well as the company's survey data.

The figures show that "child care is expensive, even though caregivers make poverty wages; that care can be difficult to find, and that, though quality is difficult to measure, only a handful of centers and family homes are nationally accredited for quality," authors Brigid Schulte and Alieza Durana wrote.

Full-time care in centers for young children costs an average $9,589 a year. The average cost for in-state college tuition is $9,410, the report said. The price tag for an in-home caregiver averaged an annual $28,353, ranging from $25,744 in Wisconsin to $33,366 in the District of Columbia.

Poor marks for U.S. child-care costs, quality and availability threaten further harm to the labor market, the authors noted. One-fifth of families use a patchwork approach to care, cobbling together more than one type of child-care arrangement in a typical week, according to the report.

"When parents can't find affordable, quality child care, their only alternatives are to cut back on work hours, seek alternative work arrangements, look for care on the unregulated, cheaper 'gray market,' rely on an informal network of families, friends, and neighbors, or even exit the labor market completely," they wrote.

Labor-force participation already is lingering near four-decade lows. The share of Americans who are employed or looking for a job has plummeted to 62.8 percent as of August, close to the 62.4 percent reached a year ago that was the lowest since 1977.

The authors made four recommendations: universal paid family leave, better cash assistance programs, high-quality universal prekindergarten, and more programs aimed at dual-language learners.