Much of the country has recovered from the national recession, but one group that continues to struggle is perhaps the most vulnerable — children living in poverty.

Nationally, the number of children living in poverty increased from 18 percent in 2008 to 22 percent in 2013, according to the “Kids Count Data Book” released last month by the Annie E. Casey Foundation.

The numbers are similar in Pennsylvania, where the percentage rose from 17 in 2008 to 19 in 2013. That means an estimated 516,000 children were living in poverty in the state in 2013.

Supporters of early childhood education are using the figures to buttress their case for more resources for pre-K education. They point to statistics that show a growing portion of Pennsylvania’s children are not attending preschool, particularly economically disadvantaged children.

The Kids Count report found that the percentage of Pennsylvania children not attending preschool was 53 percent in the two-year period between 2011 and 2013, an increase from 51 percent in the previous two years. The national figure is 54 percent.

For families with an income below 200 percent of the poverty threshold, the percentage of children not attending preschool climbed from 61 percent in 2010-12 to 64 percent in 2011-13 in Pennsylvania, surpassing the national number that held steady at 63. For a family of four, this income level would be $46,566 a year.

The Legislature and governor still have not agreed on a budget for 2015-16, but the governor’s proposed spending plan calls for $256.5 million combined for Pre-K Counts and Head Start Supplemental Assistance, both of which provide preschool education, an increase of about 88 percent, or $120 million. If approved, that would add about 14,000 children to the 17,000 now served.

Laura Speer, associate director for policy reform and advocacy at the Casey Foundation, said early childhood education has a significant impact. “If children are better prepared for kindergarten, then they’re better prepared for fourth-grade reading.”