Unfortunately, that number has been co-opted by other "credible" sourcesmaking it difficult to sort out.
Oh, so it's like Kellerman's data, but for the 21st century.
For those who don't remember, Arthur Kellerman did a study in the 1980's in which he claimed that someone was 43 times more likely to be a victim of gun violence if they kept a gun in the home. He never provided raw data, his methods of collection were suspect, and he later recanted to some extent. However, the media picked up on that number, and the horse was out of the barn.
I'm seeing a real parallel here.