C31 obtains its viewing figures from OzTAM, the official industry source for television audience measurement.   Figures are usually obtained quarterly. 

Summaries of monthly viewing figures are available for download as PDF files.

2009
January - April - July

2008
January - March - May - July - October

2007
January - March - May - June - July - August - September - November

2006
February - April - June - August - October

2005
February - May - September - November