The school dropout rate in Kern County rose nearly 2 percent between the 2011 and 2012 academic years despite a decrease in the number of students who make up the group that was studied, according to data released Tuesday by the California Department of Education.

The rates were calculated based on four-year cohort data, meaning they track the same group of students from grades nine through 12. The figures released Tuesday were for first-time freshmen who entered high school in the 2008-09 school year. That class theoretically would have graduated last year.

Countywide, last year's cohort of 13,533 students had declined by 229 from 2011, but the dropout rate increased by 1.81 percent to 16.9 percent.

In California, there was a 1.5 percent decline in the dropout rate between 2011 and 2012 to 13.2 percent.

State Superintendent of Public Instruction Tom Torlakson said in a statement released Tuesday that California's 1.4 percent year-over-year improvement in the graduation rate, which rose to 78.5 percent, is a good sign.

"There are great things happening in California's schools every day, and the upward climb of our graduation rate bears that out," Torlakson said. "While I am glad to announce that we are moving in the right direction, the fact remains that we must keep moving to ensure that every California student graduates ready to succeed in the world they will find outside our classrooms."

While Kern County's year-over-year performance lost a little ground, over the last three years Kern's dropout rate declined by 5.6 percent. The dropout rate was 16.9 percent in 2012, up slightly from 16.6 percent in 2011 but down from 17.9 percent in 2010.

In the Kern High School District alone, the dropout rate was 14.5 percent in 2012, up from 12 percent in 2011 with 27 fewer students.

But KHSD was still below the state's 14.7 percent dropout rate last year.

"Our overall graduation rate is ahead of the state average, and we're closing the graduation gap with our minority students," said Michael Zulfa, assistant superintendent of instruction for the Kern High School District.

In KHSD, 80.7 percent of those who started high school in 2008-09 graduated with their class in 2012. In California, only 78.5 percent graduated on time.

Also in KHSD, 77.9 percent of Hispanic students in the study group graduated last year, as did 77.4 percent of black students. That's compared with 73.2 percent of Hispanics and a dismal 65.7 percent of blacks statewide.

Moreover, the study group doesn't include fifth-year students at KHSD's continuation schools.

"Did they graduate? No," Zulfa said. "But we see it as not yet, because we're still working with them."