I would say that 137 is a fair reflection of the numbers who have left over the years. If you count, Ireland, Germany (both operational and training), Eurocontrol, Canada, Hong Kong, Bahrain, Abu Dhabi, UAE Centre, Dubai, Muscat and probably a few more I have missed, each at at least $300,000 a pop in training costs, the drain from ASA has been pretty substantial. The funny thing is you'll find most Aussie Expats would never leave such a beautiful country if they were given a fair go by their employer.
Not the case though hence the mass exodus continues, and most stay away for an extended period.