PORTLAND — Tuition at Oregon’s seven public universities will increase by an average of 6 percent next school year, under rates approved Friday by the State Board of Higher Education.

The increases, ranging from 1.5 percent at Western Oregon University to 9.9 percent at Southern Oregon University, will be partially offset by cuts in fees. Some of the fee cuts are tied to a decision by most campuses to provide optional health insurance coverage instead of making it mandatory.

The state’s most expensive school for resident undergraduates remains the University of Oregon, where tuition and fees will come to $9,310 annually — an increase of roughly $3,000 in just four years.

Across the nation, tuition has increased steadily for years at both public and private universities. In explaining this year’s rise, Oregon University System officials noted that state support declined by $132 million from 2009-11 to 2011-13, and expenses for labor, health care and the Public Employee Retirement System continue to rise.

The board approved the new tuition rates on a 9-2 vote, with the two student representatives casting the “no” votes.

Overall, the average cost of tuition and fees at the seven universities will be $7,841 next fall.