Georgia Education Department officials released graduation rate data Tuesday for the 2015-16 school year for Gwinnett County and the state's 180 other school districts.

Here are five takeaways.

1.The overall rate inched up. The graduation rate in Gwinnett rose from 78.1 percent for the 2014-15 t o79.6 percent for the 2015-16 school year.

2.Gwinnett's graduation rate is ahead of the state's average again. The 2014-15 rate in Gwinnett of 78.1 percent was slightly below the statewide average of 78.8 percent. For 2015-16, Gwinnett's rate of 79.6 percent was ahead of the preliminary statewide average of 79.2 percent. The state is waiting on data from some schools before it can finalize its average.

3. Collins Hill High led the increase. The school's graduation rate rose by more than 7 percentage points, from 83.2 percent to 90.5 percent. Sixteen of Gwinnett's traditional high schools had higher graduation rates.

4. Duluth High School had the greatest decrease. Its graduation rate declined from 82 percent to 75.4 percent.

5. Gwinnett has some work to do improving the grad rates among some subgroups. Gwinnett's graduation rates was lower than the state's among Hispanic students, those with disabilities, students described as economically disadvantaged and English language learners.

You can find test scores, graduation rates and other critical information about your school at The Atlanta Journal-Constitution's new Ultimate Atlanta School guide.