Over the last five years, the ranks of Hawaii public school children eligible for free and reduced-cost lunch — a key indicator of poverty — have swelled by 35 percent to 90,660, in a trend that’s causing increasing concern for advocates and school administrators.

Statewide, 53 percent of public school students qualify for the program, the highest percentage in at least two decades. That’s up from 39 percent in the 2006-07 school year, when 66,791 kids were eligible for the lunch subsidy offered to struggling families.

Ivette Rodriguez Stern, a researcher with the University of Hawaii’s Center on the Family, said the increase is "indicative of the economic situation" and a serious worry because of the strong link between student achievement and poverty.

Disadvantaged students locally and nationally trail behind other students on standardized tests and graduation rates.

State school food services director Glenna Owens called the growing numbers of students eligible for the program "telling" — more proof of just how hard families have been hit in the economic downturn.

The big increase in students falling into the income brackets that qualify them for free and reduced-cost lunch comes as the Department of Education is pushing a host of reforms aimed at boosting student achievement and getting more children to graduation day.

Schools statewide, including those in traditionally middle-class neighborhoods, are working to improve their outreach to the growing number of low-income students even as the schools grapple with budget cuts.

At Mililani Middle School this year, 23 percent of students qualify for the subsidized lunch program, up from 16 percent last school year and 13 percent in 2009.

"It’s quite a dramatic increase," Mililani Middle School Vice Principal Greg Nakasone said. He added that in his seven years at the school, he has typically seen eligibility percentage for the program hover in the low teens.

Nakasone said parents are struggling with job losses and wage reductions. Some families have had to move in with relatives because of the tough times.

"Parents are working a lot harder" to make ends meet, he said. "We need to support the kids a whole lot more."

Public charter schools are also seeing more students on free and reduced-cost lunch. In the 2010-11 school year, the most recent for which data are available, 46 percent of the 8,204 students in public charter schools were in the program, up from 39 percent of 7,819 kids the year before.

About 27 percent of students at Waialae School, a public charter, qualify for lunch subsidies, up from 23 percent last year. The school’s chief educational officer, Wendy Lagareta, said even families who don’t qualify appear to have a lot less "discretionary money" these days. "I think they’re looking at their own personal budgets and having to cut" spending, she said.

The free and reduced-cost lunch program, largely paid for by reimbursements from the federal government, is aimed at making sure that low-income students have at least one nutritious meal a day. Students can also eat school breakfast for free at subsidized cost, though most choose not to.

Kids in households earning at or below 130 percent of the federal poverty level qualify for free lunches. Reduced-cost lunch is available for families earning up to 185 percent of the poverty level.

In Hawaii a family of four earning no more than $33,423 a year is eligible for the free lunch program. The income limit to qualify for the reduced-cost lunch (for 40 cents) is $47,564 for a family of four.

The increase in kids qualifying for the program is being driven by growth in the free category, which made up 80 percent of all students eligible. This year, 71,161 students qualified for free lunch, up 45 percent from 2007, when there were 49,085 students eligible.

Meanwhile, Department of Education figures show the number of students eligible for the free and reduced-cost lunches is at its highest level in at least two decades. In 1990, 29 percent of students qualified. (Older data weren’t immediately available.)

The rise in students qualifying for the program mirrors a national trend, but it’s difficult to tell how Hawaii’s overall increase compares with other states.

The most recent national figures are for 2008, when 45 percent of all public school students were eligible for the program.

That year, 42 percent of Hawaii students qualified.

Stern, of the UH Center on the Family, said the subsidy program is "an indicator of economic well-being." Low-income children, she added, are more likely to face unstable conditions at home and food insecurity — both of which might affect their academic performance.

The percentage of students who qualify for free and reduced-cost lunch is used to determine whether a school is eligible for the federal Title I program, which offers extra funding to campuses where 35 percent or more of the student population qualifies for the lunch subsidy.

Of Hawaii’s 255 public schools, 186 are Title I, up from 161 in 2007.

The growing number of students in the subsidized lunch program follows several years of rising lunch prices. The cost of school lunch is poised to go up again next school year by 85 cents, bringing the price to $3.10 for elementary school students andr $3.35 for middle- and high-schoolers.

Students who get reduced-cost lunches won’t be affected by the price hikes.

Principals say the rising price of lunches might be partially behind increased applications for free and reduced-cost lunch. But they say the substantial increases are largely attributable to the economy. And they worry about many "gap-group" students whose families earn slightly higher than the income limit to qualify for the program.

Kalihi Uka Elementary Principal Laura Ahn said the percentage of children at the school eligible for free or reduced-cost lunch has grown from 61 percent in the 2009-10 school year to about 72 percent this year.

Many families that aren’t eligible still find it tough to cover basic needs for their children, Ahn said. And some are relying on the "lunch loan" program at the school, which temporarily pays for a student’s lunch if they no longer have any credit on their lunch card.

(Parents load the cards because students can’t pay with cash.)

Ahn said the front office is having to send out a lot more warning letters to parents asking them to load up their children’s lunch cards.

At Liholiho Elementary, 36 percent of students qualify for free or reduced-cost lunch this school year, up from 30 percent last year. The growth means Liholiho, a national Blue Ribbon school, will be a Title I campus for the first time next year, said Principal Christina Small.

"There is a big jump (in eligibility) due to the economy," Small said, adding that the campus is also trying to work with its "gap group" parents. For example, she said, the school hopes to get a grant to offer parents classes and other tips on how to prepare healthful and cheap meals.