Productivity Commission report titled Section 8 'Corrective services' notes that in 2017-18 Total net operating expenditure on prisons and community corrections, including depreciation, was $4,415,968,000 ($4.416 billion) - a real increase of 35% from five years earlier in 2012-13 when it was $3.272 billion (See $3,272,039,000 in 2012-13 and $4,415,968,000 in 2017-18 a mere 5 years later).   It further increased to $4.846 bil in 2018-19 and to $5.091 bil in 2019-20.
During the same five year period, the Australian population increased from 23.13 million at June 2013 by 1,861,500 to 24.99 million at June 2018 - an increase of 8.05%

Click on Table 8A.1 - Total net operating expenditure and capital costs on prisons (excluding Community corrections) in 2018-19 was $4.886 billion

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