The cost to taxpayers of births on American soil to illegal immigrants is about $2.4 billion every year, according to a new study.

The Center for Immigration Studies said its research is based on an analysis of the Census Bureau's American Community Survey. The government data, CIS said, "provides a good picture of births to immigrant mothers, including the mothers' demographic characteristics."

"These characteristics allow us to estimate the likely number of births to illegal immigrants nationally, as well as births by state and by large metropolitan area."

Read a summary of the study

Citing 2014 government statistics, CIS said its best estimate is that legal immigrants accounted for 12.4 percent (494,000) of all births and illegal immigrants for 7.5 percent (297,000).

The number of illegal immigrant births is larger than the total number of births in any state other than California and Texas.

The United States automatically awards citizenship to anyone born in the country, including those born to temporary visitors or illegal immigrants.

The estimated 28,000 births to illegal immigrants in the Los Angeles metro area alone is larger than the total number of births in 14 states and the District of Columbia.

CIS pointed out that among the native-born, 42 percent of new mothers are either uninsured or on Medicaid.

The rate is even higher among new mothers who are legal immigrants (47 percent) and higher still for new mothers who are in the United States illegally (67 percent).

Almost all of these births are likely paid for by taxpayers, CIS noted.

Of all births likely paid for by taxpayers, about one in four (429,000) was to an immigrant (legal or illegal).