AUGUSTA — Maine leads the nation in the percentage of 2-year-olds properly immunized, Gov. Angus King announced Thursday.

“Maine has the distinction of having the highest immunization level ever recorded in the United States,” King said at a news conference.

Nearly nine of every 10 of Maine’s 2-year-olds got the recommended doses of childhood vaccine last year, the state Bureau of Health says. Nationally, one in four children are not properly vaccinated by age 2, the agency said.

For about the last five years, Maine has had an immunization program that gives immunizations to health care providers for free. In return, the providers cannot charge their patients more than $5.

Four HMO’s contributed about a tenth of the program’s estimated $7 million budget, with the federal government picking up the rest of the tab. Blue Cross-Blue Shield of Maine, Healthsource, NYLCare and Harvard Pilgrim came on board last summer when financial problems jeopardized the program.

Maine distributed over 300,000 doses of vaccine last year to about 500 public and private providers across the state.

The U.S. childhood immunization rate rose from 55 percent in 1992 to 75 percent by early last year.

Maine’s immunization rate was 74.3 percent in 1994 and 84 percent in 1995. The state has not had a child die of a vaccine-preventable disease in this decade, said Dr. Dora Mills, director of the health bureau.

Maine had about 27,000 children under age 2 last year.