We have three indoor ranges within an hour of me and none of them has EVER had a suicide.
It depends on area and demographics, as well as other factors. Our location had one in the late 1990's under prior ownership, and we were fine until 2009. Then we had one, followed by another roughly two years later. Other ranges in the area have had several within months of each other.
It's not something a range owner wants publicized for many reasons, and the media doesn't often report it. It seems to be more focused in urban areas.
I'm not saying it's a foregone conclusion, but it's a strong possibility, and one worth preparing for.