government revenue grows 24% since 2008, page-18

"Company tax and resource rent taxes represented around 5.4 per cent of GDP in 2006-07, but fell to around 4.1 per cent in 2010-11. This is partly due to lags in the recovery of company income tax receipts, because losses accumulated during the GFC are now being claimed against current profits. The GFC also caused capital gains tax receipts to fall by around two-thirds from their peak of 1.5 per cent of GDP in 2007-08. Asset markets have remained sluggish and there is an unprecedented stock of losses that remain to be absorbed by future gains before tax will be payable. Capital gains tax receipts are predicted to recover, but not to reach their pre-crisis share of GDP.

There are structural influences also at work on the revenue base. Even with an enduring global recovery, we have not seen a similar recovery in revenues. The first phase of the mining boom before the GFC saw a large increase in company tax receipts driven by high commodity prices, but the second phase hasn’t seen a similar increase in tax receipts, because of the dramatic increase in investment in new projects.

The write down in tax receipts following the GFC is in stark contrast to the windfall revenue the previous government received during the first stage of the mining boom. From 2003-04 to 2007-08 Budgets, including the forward estimates, the previous government received an additional $334 billion in unexpected revenue, and spent an unsustainable $314 billion in new expenditure and poorly targeted tax policy.

By contrast, this Government has faced substantial write-downs in tax receipts and is undertaking one of the largest fiscal consolidations in history. Since the GFC, revenue write-downs over the 5 years to 2012-13 amount to around $150 billion."

http://www.budget.gov.au/2012-13/content/glossy/tax_reform/html/tax_overview_02.htm