i agree with Hoti, everything ive read says 1/200, but also as maruschke says it also depends on the skill of the person performing it.
If you get someone who hasnt done many i would say the risk would be much higher, whereas someone like the lady i seen who does 7-10 procedures a week for the last 15 years or so i would believe to have a lower risk.
Unless WA gov have chosen to give a different statistic