Marjory Stoneman Douglas High School in Parkland, Florida last week joined a grim list of murderous US school shootings, alongside Sandy Hook elementary school and Columbine high school.

But what about Marshall County High Schoolin Benton, Kentucky? Or Salvador Castro Middle School in Los Angeles, California? These were both sites of school shootings with casualties last month.

It might seem bizarre that school shootings have become such a regular occurrence in the US that unless there are many fatalities, the attention is often only fleeting.

Even before the deaths of 17 young people in Florida last week, a U.S. education news organization had decided there was an urgent need to make sure that every such incident was counted and publicly recorded.

Education Week, which usually covers stories about teachers and education policy, launched a year-long school shooting tracker, in a project called "School shootings this year: How many and where."

"There's a danger of being desensitized. We shouldn't dismiss any of them as routine," says Kathleen Kennedy Manzo, the news organization's managing editor.

"You have to stop and think this is a big event."

Read the full article about counting every school shooting by Sean Coughlan at BBC.