If I recall correctly, Canada and New Zealand both completed their regulatory review process within five years.
Papua New Guinea was the smart state - they adopted the NZ regulations, using Australian Aid.
Somewhere back in PPRuNe, possibly in this thread, it was suggested the regulatory review process has cost $150 - $200 million so far. As I know the identity of the user that posted the comment, I know they were in a position to have accurate information.
Sadly, this has been quite consistent, right back to the first Civil Aviation Department, as an offshoot of the Department of Air (if I have those early titles correct).
The old Department of Civil Aviation was far from perfect, but it was a darn sight more user friendly than it's successors, the CAA and CASA!