Sonoma County’s overall health ranking has fallen to No. 7 in the state, down two places from last year in an annual survey of health in California.

Last year, Sonoma County ranked fifth among the 57 counties in the County Health Rankings analysis compiled by the Robert Wood Johnson Foundation and the University of Wisconsin Population Health Institute.

This year, it was knocked out of the top five by Napa and Orange counties. Raquel Bournhonesque, a County Health Rankings public health representative, said counties often move up or down the list relative to how other counties perform. The real value in the ranking is to give county health officials and leaders the health measures needed to plan broad-based public health strategies, she said.

“The County Health Rankings show us that where we live makes a difference in how well and how long we live, and that there are many factors that influence health,” Bournhonesque said.

The report shows that the rate of sexually transmitted infections (using chlamydia infections as a marker) is on the rise in Sonoma County, going from 332.3 chlamydia cases per 100,000 in 2014 to 376 cases in 2015, the most recent year for which such data is available.

High school graduation rates were another area of concern highlighted in the report. Sonoma County’s graduation rates have improved since 2011, when the health ranking was first launched. But the county’s rank of 83 percent of ninth-graders who graduate within four years is far below the rate of 95 percent for top-performing counties. Bournhonesque said the report highlights certain county public health issues that might be hidden behind seemingly positive public health measures.

For example, the county’s teen birth rate of 15 births per 100,000 females between age 15 and 19 is far below the state’s rate of 24, and matches the nation’s “top performers.” But a breakdown for that metric shows that Latina teens have a birth rate of 30, while white teens have a rate of 6.

“No one in America should have less of a chance to be healthy because of where they live, how much money they make or the color of their skin, and yet our analysis shows that’s what’s happening,” Bournhonesque said.

Lake County ranked dead last in the survey of 57 counties, down one spot from last year. Mendocino County ranked 44th in the state, also dropping a spot from last year.