Yes, that figure is probably right. I did my first parachute jump in the summer of '98, a year before this study. It was a static line jump, using a round canopy; ancient stuff even then! I had wanted to skydive for a long time, so it wasn't a "charity jump."

However, almost everyone else on my course was - they were really young as well, a bit naive and maybe a little dazed by the idea of jumping out of a plane. Some of them were Chinese/Korean students, with a very, very rudimentary grasp of the English language; I genuinely have no idea how they all passed the course, but they did. When they went on to jump, I think just under half of them ended up with broken legs/sprained ankles and so on. If my memory serves me right during the same drop the jumpmaster managed to kill himself too.

To sum up, 11% sounds about right.