The 799million figure I got from this article - http://www.motoring.com.au/motorspor...d-views-48996/
There's also one specifically about the Australian round - http://www.rallyaustralia.com.au/glo...lly-australia/
And some data from the past. 2002 - http://www.autosport.com/news/report.php/id/31147
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Television has many different statistical "outputs" and you can always manipulate statistics. Ratings, reach, share, etc. Just read the first article to see how other sports are doing.