Education Secretary John King addressed a letter to school administrators around the country Monday urging them to abandon corporal punishment of students.

Twenty-eight states and the District of Columbia prohibit corporal punishment in school altogether, while seven do not address it directly in statute: Florida is one of 15 states with laws explicitly permitting corporal punishment, largely in the form of striking students on the rear with a wooden paddle.

“These data shock the conscience,” Secretary King told reporters in a conference call Monday, referring to the more than 110,000 instances of corporal punishment nationwide reported by the Department of Education’s Office of Civil Rights.

According to state data, a handful of counties clustered in the Florida Panhandle and west of Jacksonville account for the lion’s share of the 1,600 incidents of corporal punishment reported in Florida in 2015. More broadly, the practice has declined dramatically, down more than 90 percent since 1990, and by half between 2010 and 2015. Many districts, including those in South Florida, do not allow corporal punishment at all.

Santa Rosa County Schools, which used corporal punishment on close to 300 students in 2009-2010, is one of several districts to end the practice recently over fear of litigation. “The situation I’m recalling is when a parent came to school because we paddled the child. A couple of hours later we were served notice of a complaint by the Department of Children and Families (DCF),” said Superintendent Tim Wyrosdick. “That created a different picture, and that litigation or threat of litigation became very real to our employees.”

Related: Your Guide to Corporal Punishment in Florida Schools

Wyrosdick said reactions from parents were split. While corporal punishment was used as a measure of last resort, he said, it was often parents themselves who requested paddling when notified of children’s bad behavior in school. “That’s how they were disciplined as children, and that’s also how they discipline their children today,” he said.

Wyrosdick said some parents preferred to have their children punished physically rather than the alternative of being summoned to school for a meeting with administrators, or supervising their kids during an outdoor suspension. Others called to tell the district eliminating the policy was “the right thing to do.” Either way, Wyrosdick said with a sigh, “We’ve adapted.”

“It opened up a different conversation about, you need to seek some professional help for your child, something far beyond what we’re able to provide at the school,” he said.

In 2009, then-Gov. Charlie Crist signed legislation requiring school districts that used corporal punishment to review the policy at a public meeting every three years.

Walton County officials heard from parents on both sides, according to Mark Davis, an attorney who served on the county school board at the time. Ultimately, the prospect of DCF investigations and the evolving views of district staff led the board to eliminate corporal punishment altogether during the 2014-2015 school year. “We probably wouldn’t have done it,” Davis said, “but our principals came to us—they felt there were other means of discipline.”

Secretary King’s letter cited research showing that corporal punishment is counterproductive and that it is used disproportionately on boys and on black children, as well as students with disabilities. In fact, until it eliminated corporal punishment, Santa Rosa County, for example, had a policy that prohibited paddling girls.

South Florida Congresswoman Frederica Wilson said those very arguments around gender and racial disparities contributed to eliminating corporal punishment in Miami-Dade schools more than 25 years ago, when she was the principal at Skyway Elementary School.

“Principals were governing not so much by corporal punishment as by the threat of corporal punishment,” said Wilson, acknowledging that she herself had occasionally ordered staff to use corporal punishment as a principal. “It was a part of the culture of the time,” she said.

That culture, Wilson added, has evolved incrementally over her lifetime. “When I was in elementary school, it wasn’t nothing for a principal to pick up a ruler and hit a child. Or if you couldn’t write correctly, they would hit you on the knuckles. It was children who were basically being abused,” she said. “As time went on, It was used out of habit, but you don’t really need it.”