Enrollment has been going down for more than two decades due to long-term demographic changes. New Hampshire’s population has been aging, and the number of school-aged children has been declining. That’s in line with trends of diminishing enrollment from around the country, according to the state Department of Education. At the start of the 2024 school year, there were about 162,660 students enrolled in public schools, according to state data.

Having fewer students can drive up the cost per student, when the same costs of operating a school building and paying teachers are spread among fewer students. But beyond that, costs are also going up.

Compared to other states and Washington, D.C., spending in New Hampshire is relatively high — in fiscal year 2022, it ranked 7th highest for school spending per student, according to the US Census Bureau.

New York topped the list at $29,873 per student, with neighboring Vermont at number four ($24,608), followed by Connecticut ($24,453), and Massachusetts ($21,906). Rhode Island ranked ninth highest, at $19,962 per student. Nationally, average spending per pupil in 2022 was $15,663, according to the Census Bureau data.

It’s no surprise that high spending is clustered in New England and the Northeast, more broadly, where the cost of living is relatively high, according to Christina Pretorius, policy director at Reaching Higher NH, a nonprofit education think tank.

“It’s just the nature of living in a New England state,” she said. “I was in Oklahoma, and gas was a drastically different price than it was here, as were groceries.”

Education spending in Oklahoma was significantly lower; at $10,890 per pupil, it ranked 48 in the Census Bureau data.

A lower cost of living can translate to lower costs for running a school building or lower educator pay. Plus, Pretorius said, other states have to adhere to different educational standards, with varying requirements, such as the ratio of teachers to students, for example.

New Hampshire is also a relatively rural state, where education costs are spread among fewer students. That’s especially noticeable in some of the most rural parts of the state, such as in Pittsburg, the northernmost town in the state which abuts the Canadian border. Pittsburg’s cost per pupil was the highest in the state, at nearly $44,500, according to the Department of Education.

And there’s a lot of local control in New Hampshire — where local voters get to make budgetary decisions about things like staffing levels.

But the education commissioner said the numbers indicate it may be time for change.

“The persistent trend of declining student enrollment combined with rising costs creates substantial financial strain on school districts, taxpayers and communities, necessitating new and creative approaches to educating our children in a system that can be sustained over the long term,” Education Commissioner Frank Edelblut said in a press release.

An analysis from Reaching Higher found that from 2014 to 2024 overall spending went up by 7.4 percent, growing from $3.5 billion to $3.8 billion after adjusting for inflation. The actual cost in 2014 was about $2.8 billion.

There were a few specific programs contributing to the increase.

Spending on special education, bilingual, and gifted and talented programs has gone up by about 10 percent after adjusting for inflation. In 2024, this made up about 20 percent of total spending.

Other instructional programs such as school-sponsored co-curricular activities, sports, and summer school went up by 15 percent in the past decade, but it’s a relatively small slice of overall spending, at less than 2 percent.

Student support services also went up significantly, rising 18 percent in the past decade, to fund social work, guidance, health, psychological services, and speech pathology. That now accounts for just over 8 percent of total spending.

General administration and business expenses increased by about 21 percent, and account for about 4.5 percent of overall spending.

Operating school buildings went up by almost 17 percent in the past decade, and at $350 million, it accounts for about 9.3 percent of overall spending.

Pretorius said just looking at the cost per pupil is a myopic view of school funding issues. In the past 10 years, student needs have changed, she said, pointing to mental health needs during and after the pandemic, as one example.

“Cost per pupil is just one measure,” she said, “but it’s certainly not the whole picture.”

In her view, the cost of operating a school has actually remained relatively flat over the past 10 years. And she warned that lowering the cost per pupil might entail cuts that could harm student learning — like firing a teacher, reducing programs, or decreasing support available to students.

Andrew Cline, president of the Josiah Bartlett Center for Public Policy, a free market think tank, said education costs are so high in New Hampshire because local voters choose to spend money on public schools, even if it means raising taxes.

“People like their public schools and want to spend more money on them,” he said. “That’s what’s mostly driving the overall spending increase and the per pupil increases.”

A 2023 study from his think tank found education spending increased 40 percent from 2001 through 2019, with a large portion of spending dedicated to hiring new staff.

The study found that many of the new hires were administrative staff, noting a 57 percent increase in district administrators. Support staff grew 31 percent, paraprofessionals and aides grew 40 percent, while teachers only grew about 2 percent.

Amanda Gokee can be reached at amanda.gokee@globe.com. Follow her @amanda_gokee.