In the last 15 years, the number of children enrolled in California’s low-income health program has steadily grown.

Hospital discharge data for children illustrates this trend, according to a report released earlier this month by Kidsdata using figures from the California Office of Statewide Health Planning and Development.

In 2002, roughly equal numbers of children with private insurance and with Medi-Cal, the state’s low-income health program, were discharged from hospitals.

By 2015, the number of Medi-Cal discharges had grown nearly 10 percent, to 54.7 percent of children’s hospital discharges statewide. Meanwhile, 35.4 percent of children discharged from California hospitals that year had private coverage.

Medi-Cal enrollment still varies by county, however. In 2015, Medi-Cal discharges for children ranged from a high of 74.3 percent in Tulare County, in the Central Valley, to 23.6 percent in San Mateo County, in the Bay Area.

As a whole, the Central Valley and rural Northern California, such as Siskiyou, Tehama and Trinity counties, had the highest rates of Medi-Cal discharges for children that year.

For the state as a whole, in 2015 other government programs paid for 7.3 percent of children’s hospital discharges and 2.2 percent of families paid for the medical care themselves.

In 2002, by comparison, slightly more families—2.7 percent—footed the bill. This is likely because fewer children had health coverage then, before the federal Affordable Care Act and other state health reforms. By 2015, nearly 97 percent of California children had health insurance.

From 2013 to 2015, California insured more children than any other state nationwide, and saw the highest decline in its percentage of uninsured children. During those two years, an additional 371,000 children gained coverage.

About 10.7 million Californians—including more than half of all children in the state—are now enrolled in Medi-Cal, according to the most recent enrollment report.

Lucile Packard Foundation for Children’s Health is a Funder of both California Health Report and Kidsdata.