Teachers, doctors, pupils and statistics

I love the ambiguity in this clipping taken from Personnel Today magazine (and sorry it's wonky, that's just my usual inability to cut and/or scan things straight):


Does this mean that 12% of teachers who have been attacked by a pupil subsequently needed to visit a doctor, or that 12% of teachers have been attacked by a pupil and subsequently needed to visit a doctor?

If you can't see or don't care about the difference, you might not want to become a sub...