WomenInPoltics

http://databank.worldbank.org/data/reports.aspx?source=2&country=&series=SG.GEN.PARL.ZS&period=
The latest Australian data matches with the most recent election - http://results.aec.gov.au/17496/Website/Default.htm

These are seats of parliament held by female politicians, and obviously don't inlcude Senators, which Australia has a higher proportion of.

Year,World,Australia
2004-01-01,15.9,24.7
2005-01-01,16.5,24.7
2006-01-01,17,24.7
2007-01-01,17.9,26.7
2008-01-01,18.5,26.7
2009-01-01,19,27.3
2010-01-01,19.2,24.7
2011-01-01,19.8,24.7
2012-01-01,20.8,24.7
2013-01-01,21.8,26
2014-01-01,22.2,26
2015-01-01,22.9,26.7

This data is for the lower houses around the world, not the Senates of any country.