Aussies love their horse racing.

Another website have this title as a heading on a story, the Australian Bureau of Statistics have said horse racing ranks second among sports attended by people aged 15 years and over during the last year.

Australian Rules Football led the way (16% or 2.8 million), while horse racingTHOROUGHBREDS (11% or 1.9 million) held down a second-place ranking over rugby and motor sports, of the 1.9 million.
what number would harness racing contribute?

Other sporting events where the change in attendance rate was statistically significant were outdoor cricket (reducing from 5% in 2005-06 to 4% in 2009-10), rugby union (reducing from 4% in 2005-06 to 3% in 2009-10) and harness racing (reducing from 3% in 2005-06 to 2% in 2009-10). The only significant increase in attendance rate was for outdoor soccer which increased from 4% (0.6 million) in 2005-06 to 5% (0.9 million) in 2009-10, I went go to the futbol.
The money being made is in no way reflected in the lower numbers of people at the track.