JACKSONVILLE, Fla. -

Nearly half of Florida's high schools received an A grade for the 2011-12 school year and every Duval County school received a grade of C or above for the first time in a decade.

"We have for the first time in FCAT school grade history no D or F schools in Duval County public schools," Superintendent Nikolai Vitti said.

Preliminary grades released by the Florida Department of Education on Friday show 47 percent of high schools earned an A, 31 percent a B and 18 percent a C. The number of schools receiving an A jumped 16 percent.

Three Florida schools were given an F, down from six in 2010-11.

Seven Duval County high schools received A grades, six were given Bs and eight received a C. Andrew Jackson improved its grade from an F to a B, while Raines and Ed White improved from D grades to Cs, and A. Philip Randolph Academy and Ribault, which were two of Jacksonville's intervene schools with a failing grade two years ago, received an A in this report card.

"I don't know if anyone really knows what it feels like to take the hit knowing the level of work that you are doing in your school building, knowing how hard your students are working and how dedicated the teachers are," Andrew Jackson Principal Iranetta Wright said.

"I want to congratulate our high school principals, teachers, support staff, students, parents, and partners on their outstanding improvement. I am especially proud of the work at Andrew Jackson and other traditionally lower-performing schools," Vitti said. "Our work now rests on sustaining and accelerating the improvement into the future."

In Clay County, all seven of its high schools earned either an A or B grade. In Nassau County, Fernandina Beach, West Nassau and Yulee high schools earned As, while Hilliard High School earned a B. Baker County High School received a B.

DOCUMENT:  Grades for all Northeast Florida high schools

In St. Johns County, there were four A schools, two B schools and one C school.

The increase in the number of schools receiving an A in Florida came despite use of a more rigorous graduation rate and standards. The state Board of Education however also approved measures to ease the transition in the 2011-12 school year grading.

"This year's results reflect both higher standards and temporary safeguards the State Board of Education approved to help smooth the transition," Commissioner of Education Pam Stewart said in a news release. "As we continue toward implementing Common Core State Standards and assessments, we will continue to raise the bar as we prepare our students for success beyond high school."

The states grades its high schools based on student performance on the Florida Comprehensive Assessment Test as well as indicators of college readiness and participation in advanced classes.

Next year, high school grades will include biology and geometry end-of-course assessments.

High school grades determine school recognition funds, which reward schools that have sustained high student performance or have shown substantial student performance improvement. The Legislature approved $134,582,877 for that purpose for 2012-13.

For more information on high school grades in Florida, go to the Florida Department of Education's website.