Maryland's public schools are graduating a higher percentage of students than they have in the past 15 years but they have seen a troubling increase in the number of students dropping out.

School officials attributed the higher dropout rate to the poor economy. More than one-third of students now qualify for subsidized or free meals in school, and principals say they see more students with jobs after school and families under increased financial stress.

"Economic pressures have historically had an adverse affect on continued enrollment in high school," said Bill Reinhard, a spokesman for the Maryland State Department of Education. "Researchers have found that dropouts say they are leaving to get a job or care for a parent or relative, or they are bored by their classes, but many also come from families struggling with poverty."

The Maryland State Department of Education reported Friday that 87 percent of students in the Class of 2011 graduated, up 2 percent since 2007. State school officials say they only have comparable graduation data for the past 15 years.

Across the state, 16 of 24 school districts saw graduation rates rise and 17 districts saw greater numbers of students drop out. The two trends can occur simultaneously because some students, such as those in special education, complete high school but receive a certificate and not a diploma, and because some students stay for five or six years.

The uptick in the statewide graduation rate was in part the result of continued improvement in Baltimore City's ability to get students through school. In the city, the graduation rate has had an unprecedented 20 percentage point gain in four years.

Baltimore schools CEO Andrés Alonso gave an emotional presentation Friday on the city's statistics at Vivien T. Thomas Medical Arts Academy High School. A 6 percentage point increase in the city's graduation rate over last year, to 72 percent, was driven for the second year in a row by the traditionally at-risk, African-American male population.

"We are in the point of a marathon where we get very tired … and then we need a second wind," Alonso said. "That's where we are today. We have been resilient, and we will get to the finish line."

But the city's graduation success was not mirrored in surrounding suburban counties such as Baltimore and Anne Arundel.

Baltimore County saw a decrease of 3 percentage points in its graduation rate over the past year to 83 percent. In addition, its dropout rate increased slightly, from 3.03 percent to 3.57 percent.

While Baltimore City has long been known for a high dropout rate, 109 more students dropped out of Baltimore County schools than city schools last year. The county has a higher enrollment than the city.

Anne Arundel saw a 1 percentage point decrease in its graduation rate to 87.4 percent and a slight increase in the dropout rate.

The state also reported that 45 percent of all schools in the state, including 79 high schools, are now deemed as failing, a result of the increasingly difficult benchmarks set under the federal No Child Left Behind law. Many of the schools have just missed making enough progress to meet the targets, but 96 schools have been failing for four or five years and are on the verge of being forced into complete overhauls under the law.

Maryland is expected to apply for a waiver from the law, and is considered one of the states most likely to meet the federal requirements for one.

In Anne Arundel County, school officials noted that 11 of its 12 high schools exceeded the state graduation rate but four failed to meet targets known as "adequate yearly progress" under the law — Annapolis, Glen Burnie, Meade and Old Mill high schools. In a prepared statement, schools Superintendent Kevin Maxwell said the results were "a setback for our students and educators."

In Howard County, just one high school, Mount Hebron, failed to meet the progress standards. The county's graduation rate remained constant at about 94.3 percent.

For the second year in a row, state officials said no students didn't graduate from high school solely because they weren't able to meet the High School Assessment requirement, which went into effect in 2009.

The exams are given in biology, English, Algebra I and government, though the state will drop the government exam for the Class of 2012 as a way to save money. Students can also meet the HSA requirement by completing "bridge" projects if they do not pass a test in one or more subjects and by receiving waivers.

Leslie Wilson, the head of testing for the state, said that the HSAs have helped to push up the graduation rate because schools are focusing on getting every child to pass the test.

"Nobody fall through the cracks. No one is left behind now. And with personal attention, they graduate," she said.