[Editor's note: A previous version of this story, using data provided by Everytown for Gun Safety, said there were 18 school shootings in 2018. Everytown has since revised that number down to 17 after the Washington Post published an article disputing the group's figures. For more clarity on Everytown's data, click here.]

It's not even two full months into 2018 and there have already been 17 school shootings — more than twice as many as this time last year.

The attack on Marjory Stoneman Douglas High School in Parkland, Florida, is the 17th U.S. school shooting within the first 45 days of the year, according to Everytown for Gun Safety, a gun control advocacy organization.

Everytown has been tracking shootings in schools and universities since 2013. It reports any time a firearm is discharged within a school building or on campus, whether accidentally or intentionally and whether or not anyone has been harmed.

Seventeen people were slain and 14 people were hospitalized in the shooting at Marjory Stoneman Douglas High, authorities said. The suspect, 19-year-old former student Nikolas Cruz, was booked on 17 counts of premeditated murder Thursday, The Associated Press reported.

"No child, teacher or anyone else should ever feel unsafe in an American school," said President Donald Trump, who has resisted calls for greater gun control measures after previous mass shootings.