Cardozo High School (Marvin Joseph/The Washington Post)

D.C. Public Schools’ graduation rate increased last school year by two percentage points, to 58 percent, but the city’s public charter schools recorded a drop of nearly seven points, to 69 percent, according to new data.

The citywide average for the Class of 2014 — 61 percent — was almost unchanged from the year before, according to data from the Office of the State Superintendent of Education (OSSE). The city’s graduation rate remains far below the national average of 81 percent.

D.C. Schools Chancellor Kaya Henderson said she was pleased but “not thrilled” with the incremental growth. The graduation rate for the city’s public school system has increased five percentage points in four years.

“Still too few of our young people are graduating,” she said.

Charter schools enroll a smaller share of the city’s high school students, which means that significant changes at individual schools can have a more dramatic effect on the overall graduation rate. There were major declines in the graduation rates at two charter schools that closed or were at risk of closure last year— and two of the city’s most reputable charters also had double-digit declines — pulling the overall charter rate down.

Roosevelt High School in Petworth is one of three DCPS schools that had a double-digit increase, improving its four-year graduation rate from 48 percent to 62 percent. Principal Ivor Mitchell said the progress is the result of multiple changes in school culture and routines, including increasing participation in Advanced Placement courses, introducing individual conferences with students and expanding opportunities to make up credit through after-hours programs.

At a college and career center at Roosevelt, five full-time counselors or staff members spend their working hours pushing students to graduate, tracking their progress on spreadsheets and chasing them down in hallways to urge them to fill out their financial aid forms or get to class.

“They are always in your head, on your back,” said Tommy Thompson, 18, a senior who plans to graduate and study business administration at Bethune-Cookman University in Florida.

The four-year graduation rate is calculated by following a cohort of students who started as freshmen and graduated with a regular diploma four years later, during the 2013-2014 school year. It accounts for students who transfer in or out of a given school.

Administrators say the rate reflects the number of students earning degrees but also how well schools track down students who leave, since a school must show that a student has reenrolled in another school, whether across town or in another country. Any students whom schools cannot track down are counted as nongraduates.

OSSE also reported a five-year graduation rate for the District: 68 percent last year — 63 percent for the traditional school system and 80 percent for charter schools.

Naomi Rubin DeVeaux, deputy director of the D.C. Public Charter School Board, said that many charter schools with declines had admitted more students who were missing credits and were not ready to graduate in four years, although they are on track to graduate in five.

Among high-performing charters, Washington Latin and KIPP had declines of 11 points and 10 points, respectively, to 85 percent. Lindsay Kelly, a spokeswoman for KIPP, said the school increased the rigor of its program. She added that officials expect the five-year graduation rate for the 2014 cohort to be closer to 90 percent.

Last year, Booker T. Washington’s graduation rate dropped significantly, from 64 percent to 49 percent, in its final year before the school closed due to poor academic performance. There was also a major drop at Hospitality High Public Charter — from 76 percent to 32 percent — in the year before it relinquished its charter.

IDEA Public Charter School’s rate fell from 75 percent to 48 percent. Head of school Justin Rydstrom said he believes that the drop is a reflection of poor record keeping and tumult at what he called the “worst” point in the school’s history. The charter board moved to close the school in 2012, but the school won approval to pursue an aggressive turnaround instead.

The city is focusing new attention on reducing the large number of high school dropouts. A report released in September found that graduation rates varied widely by school.

The rate at Columbia Heights Education Campus, a selective high school, rose from 73 percent to 84 percent, and H.D. Woodson High’s graduation rate went from 44 percent to 60 percent, a change its principal attributed to an increased focus on attendance, schoolwide assemblies on graduation and new opportunities for credits.

Among the city’s comprehensive high schools, graduation rates ranged from 39 percent at Anacostia to 76 percent at Wilson High School. Banneker High School, a selective school, had a 100 percent graduation rate.

Henderson said the slow pace of improvement in the overall graduation rate “makes the case” for a $13 million investment in improving the city’s high schools next year. Her budget calls for enough staffing to offer at least six Advanced Placement courses and 20 elective courses at every comprehensive high school. Many schools have been lacking enrichment opportunities such as marching band, yearbook and debate.

Henderson said she plans to look at the successful schools to borrow best practices to boost graduation rates elsewhere.