WASHINGTON - Maryland's high-school age population grew by 10,598 people from 2003 to 2004, making it one of the fastest-growing age groups in the state, according to Census Bureau estimates scheduled to be released Thursday.

The 3.35 percent increase in 14- to 17-year-olds in Maryland outpaced the growth rate for the same age group nationally, and helped drive the demand for new school facilities and more teachers in the state.

"It's not just facilities. It's the resources -- for textbooks, instruction material, teachers," said Carl Smith, executive director of Maryland Association of Boards of Education in Annapolis. "It's part of the challenge of meeting the needs of children."

But while the high-school age group grew, the number of children coming up behind them fell over the last year, according to the national and state population estimates from the Census Bureau. The number of 5- to 13-year-olds fell by 0.9 percent, or 6,292 children.

Younger school-age children were in one of only two age groups to drop between 2003 and 2004 in the state. The other was adults from 25 to 44, whose numbers fell by 23,079 people, or 1.42 percent.

Actual enrollment in public secondary schools rose by 4,465 students from 2003 to 2004, when enrollment reached 406,930 students, said Kathie Hiatt, managing director of research at the Maryland State Teachers Association, citing state Education Department data.

Some of the increase in the high-school population can be attributed to people from other states and countries who are attracted by the state's economy, said David Lever, the executive director of the Interagency Committee on School Construction. The committee oversees public school construction in the state.

Smith said he believes that a consensus has been reached on all levels of government to increase money for school facilities, but that construction has fallen behind demand because "funding has not kept pace."

Maryland State Teachers Association President Patricia Foerster agreed that many schools are "over capacity."

Indicators of a swelling student body include the presence of temporary classrooms outside school buildings and lunch periods that have to begin in mid-morning to accommodate everyone, she said.

"The idea of eating at noon is nonexistent," Foerster said.

More serious concerns include a shortage of teachers in science, math, special education, and English as a Second Language, she said.

Smith said the shortage of qualified teachers in biology, chemistry, physics and advanced mathematics is compounded by Maryland's competitive job market. People with specialized expertise can work with the National Institute of Standards and Technology or IBM, instead of teaching in public schools, he said.

But while high school enrollment grew, elementary school enrollment shrank, consistent with declines in that age group. Hiatt said that elementary school enrollment fell by 8,017 students in one year to 458,631 in 2004, a 1.72-percent decline.

Public school enrollment overall remained largely unchanged in Maryland, inching up from 869,113 students in 2003 to 870,961 in 2004, she said.

Even with the falling numbers in the lower grades, Lever said there may not be relief on the horizon. The need to finance primary school projects, such as repairing old schools, will not be diminished, he said.

Smith agreed with Lever that it is impossible to predict now whether the declines in the lower grades will translate into a shrinking high school population in the future.

"It doesn't work that way," said Smith, who said he does not have a crystal ball to peer into the future. "There are forces at work that would confound simple-minded projections. You can anticipate, but can't predict."