AUGUSTA, Maine — Public school enrollment in the United States will hit an all-time high this fall with nearly 50 million students, but in Maine the number of students is expected to decline again, this year to below 190,000.

“We believe we will continue the downward trend,” said Education Commissioner Susan Gendron. “We have been losing 3,500 to 4,000 students a year, and we expect that will continue.”

She said all of the data reported from local schools indicate the trend will continue for several years and will hit the expected low point of 175,000 students in 2013. She said the growth after that point is expected to be small.

A federal study released earlier this summer indicated the largest factor in the increased school enrollments nationally is the growth of minorities, with the Latino population growing the fastest. The study indicated about 43 percent of all students in the nation are members of a minority group.

“We do not have the demographics of many other states that are seeing growth,” Gendron said.

But, she said, there will be growth in some school districts while others decrease more rapidly than the state average. She expects the trend to be fewer students in northern and eastern communities with a little growth in some southern Maine communities.

Gendron said that when she took office in 2003 there were about 205,000 students in Maine. She acknowledged that even though there are significantly fewer students, the cost of elementary and secondary public education in the state has increased every year.

“Costs are climbing every year, and the other factor is that we have not seen comparable declines in staffing in our districts,” she said. “Those have been decisions at the local level to continue staffing levels even though there are fewer students.”

Gendron said that would start changing with the creation of new school administrative structures across the state. She expects the state to reach the goal of no more than 80 administrative units instead of the current 290 by the end of the year. Those administrative units oversee 670 elementary and high schools across the state.

“But students will not be seeing many changes as they go back to school,” Gendron said. “Most of the reorganization plans are waiting for a vote and others are being worked on by school units.”

She said many communities will vote on proposals at the November elections and the new units will be formed after that. She said students starting school a year from now will see the changes being worked on across the state and she expects they will see fewer administrators.

Gendron said many students may see changes in the school food programs this year, with the start of school breakfast programs funded by the Legislature in some schools.

“We expect many schools will take advantage of the program and offer breakfast along with lunch,” she said.

Last year, more than 18.6 million lunches and 5.7 million breakfasts were served. State officials hope all schools will eventually add the breakfast program, which has both state and federal subsidies.

“We know that a student that has breakfast learns better in the classroom,” said Walter Beesley, director of the Department of Education’s school nutrition program. “All of the studies show it is very important.”

He said students likely would see changes in the menu this fall, as schools cope with the higher cost of food. He said many schools are hard pressed, but held a conference earlier this year to work on strategies to stretch food dollars.

“We did have an increase this year in the federal reimbursement rate, but it is not keeping pace with increased costs,” Beesley said.

Many schools started to change menu items last year in response to higher food costs, a move that upset students in many districts. Officials say that trend will continue this year.

“Unfortunately, a lot of the things they like are expensive,” said Noelle Scott, nutrition director for Bangor schools.

Gendron said some schools have not been able to hire all the teachers they need, but that happens every year and she expects school districts will shift teaching resources, use substitute teachers and do what is needed to make sure all classes are covered.