It is 20 years since this was last done by BITRE. The report based on info provided by the industry does not inspire confidence in aviation industry business acumen. See:
https://bitre.gov.au/publications/1996/report_095.aspx
Then, the claim was that CAA cost recovery and FAA charges were sending the industry broke. Total of all Government charges turned out to be 3 - 5% of operating costs.