All the groups pay more than the 10 percent-of-income limit recommended by the federal government, according to the study, which was compiled with state, federal, and nonprofit group data.
While the state has strict standards for child-care centers, it ranked close to last in enforcing them, the advocate's report states. According to national research by Child Care Aware of America cited in the report, New Jersey ranked third for center-based child-care program standards but 46th for center oversight. The ranking for home-based providers was even worse; they are not required to be licensed by the state.
State spokesmen did not comment on the report.
Experts say the first five years of life are crucial to a child's development. For most New Jersey children, at least some of that time is spent in some form of care by people other than their parents.
According to the report, more than 412,000, or 66 percent, of New Jersey children under 6 are in households where all parents work. In Burlington County, it is 73 percent; Camden County, 72 percent; and Gloucester County, 69 percent. Essex and Cumberland Counties are the highest in the state at 74 percent.
"When it comes to child care, there is a lot at stake," said Cecilia Zalkind, executive director of the advocacy group. "Kids need nurturing care, especially during those first years, so they grow and develop. Parents need care, so they can provide for their families."
Recommendations in the report include posting child-care center inspection and violation assessments online, hiring more inspectors, doing more outreach to expand child-care assistance access, and looking into enacting a state child-care tax credit.
The advocates called for statewide expansion of Grow NJ Kids, a pilot of a child-care rating system that would include professional development for early childhood education, parent engagement, and creation of a statewide database to measure progress. The state wants to expand it, but its reach would still be limited in five years, the report said.
"The state plans to move that forward, but it's a very slow process," Zalkind said.
According to the study, 37 states have child-care rating systems, including Pennsylvania's Keystone STARS, which the report praised.
For center-based care, a New Jersey family of four in poverty, with an income of about $23,000, pays 88 percent of household income for infant and toddler care if that family cannot access state or federally funded care.
Single mothers in the Garden State, earning less than $28,000 on average, pay 73 percent of their income for center care for a baby and a toddler.
The typical low-income family that pays 44 percent of its earnings on care for two children makes about $46,000 annually.