Despite what Henry County School System officials anticipated, enrollment for the 2012-13 school year rose slightly.

Enrollment for 2011-12 was 39,687, which jumped to 39,920 this year, according to numbers tallied at the end of October by the school system.

“We anticipated decreased enrollment,” school system spokesman JD Hardin said. “That’s good news to us that we have more students here in the county.”

Enrollment decreased in 2011-12, a drop from the 40,791 enrolled in 2010-11, which is why the county was expecting another decrease.

“We really can’t attribute it to one factor or another,” Hardin said of the unexpected increase. “We feel that, I’m sure like in all situations, the economy has something to do with it in some form or fashion.”

The decrease in 2011-12 was the first decrease the school system had seen since the 1976-77 school year.

“Every year after that, we saw pretty sizeable gains in the population,” Hardin said.

Some of the largest jumps were an 8.4 percent increase in 1988-89 and a 10.4 percent increase in enrollment in 1995-96.

The 1998-99 school year was the first time the county crossed the 20,000 mark. The 30,000 mark was crossed in 2004-05.

“In six years we saw 12,000 students enter the district,” Hardin said.

The 40,000 enrollment mark was crossed in the 2009-10 school year. Increases have been gradual since until the 2011-12 drop.

School systems do not report their enrollment numbers until the fall to allow enrollment to settle in the event students transfer in or transfer out.

“There are any number of factors that can come into play,” Hardin said.