The number of children attending public schools statewide has hit its highest level in six years, thanks in part to a baby bump that increased the size of this year’s kindergarten class and the growing popularity of charter schools, which saw an 11 percent increase in enrollment.

Education officials could not say how much of the enrollment increase is linked to families turning away from private schools because of the economic downturn. But officials did say that 1,000 fewer students left the public school system this year compared with 2010.

Since 2007, private school enrollment, which accounts for about 20 percent of Hawaii’s school-age population, has declined about 5 percent.

Officials also attributed the increase in public school enrollment on a larger kindergarten class, thanks to a large number of babies in 2006. Officials also noted that last year’s senior class was much smaller than average.

Department of Education figures released Wednesday showed the enrollment count for the state’s 255 public and 31 charter schools is 181,213 students, up 1.7 percent from last year.

Enrollment has not been that high since the 2005-06 school year, when there were 181,258 students in public and charter schools.

DOE figures show regular public schools saw their enrollment increase this year by 1.3 percent to 172,104.

The higher enrollment is spurring the cash-strapped DOE to seek additional funding from the Legislature. The department plans to ask for about $10 million in additional money for the 2012-13 school year, which would be distributed to schools through the weighted student formula.

The DOE’s supplemental budget request is also expected to include $42 million for student bus services and $2.5 million to preserve adult education programs.

Meanwhile, public charter schools saw statewide enrollment go up by about 900 students from last year, to 9,109. Charter schools, which educate about 5 percent of the state’s public school students, have seen rising enrollment for years.

Roger McKeague, executive director of the Charter School Administrative Office, pointed out that several charter schools have sizable waiting lists and have not completed their enrollment tallies for this year.

He said the enrollment increase shows that awareness about charter schools is growing.

"With the 31 different charters, there’s a whole lot of different alternatives," McKeague said. "For any given students, it might just be a better opportunity because of their learning style or area of interest."

Charter schools are publicly funded but are not under the Department of Education. Instead, their charters are overseen by local school boards whose authority can be revoked by the Charter School Review Panel.

Among regular public schools, the greatest growth areas were Leeward and Central Oahu, where new housing developments have pushed up population growth. Enrollment in Leeward Oahu schools increased this year by 2.1 percent, or 798 students, to 39,537. In the Central District, enrollment went up 1.4 percent to 32,964 students, an increase of 466.

Those enrollment figures are putting increasing stress on campuses already over capacity.

Campbell High, the largest high school in the state, saw its enrollment grow by 129 students this year, or 5 percent, to 2,768.

The school, established in 1962, was built to handle 2,000 students.

Corey Rosenlee, a social studies teacher at Campbell High, said the enrollment is getting out of control. The school has had to put in more portables, is constructing a new classroom building and has taken over classrooms at Ilima Intermediate, which is next to Campbell.

This year, he said, his classes have about 40 students. In the past, they have been in the mid-30s. Adding more bodies to classrooms that aren’t air conditioned makes it difficult to learn, he said.

"My classes are huge," Rosenlee said. "The state really needs to start moving on East Kapolei High."

There is no timeline on the books to build the new school, whose construction depends on other new development in the area. It is also unclear when the state would have the $120 million to build the campus.

Second to Campbell High in size is Farrington, with 2,483 students (down from 2,521 last school year). Mililani Middle is the largest intermediate school, with 1,722 students. Kapolei Middle is second, with 1,406 students.

Holomua in Ewa Beach, with 1,375 students, is the largest elementary school, followed by August Ahrens in Waipahu, with 1,374.

Meanwhile, Niihau School has the smallest enrollment in the state, with just 18 students in kindergarten through 12th grade. The next smallest is Kilohana Elementary on Molokai, with 67 students in kindergarten to sixth grade.

The largest charter school is Hawaii Technology Academy, whose enrollment is listed at 1,071 students in kindergarten to 12th grade. Charter school officials note that those numbers are not final.

While the Leeward and Central Oahu districts saw sizable growth this school year, Windward Oahu was the only district to see its enrollment decline slightly, by 41 students.

The Honolulu District’s enrollment grew by 0.9 percent, or 283 students, to 31,251.