Hi,

My database contains only Metropolitan races....

Overall
17,617 clear favourites
30.44% S/R
13.18% Loss On Turnover.

Whether consecutive or not it will even out unless you can find a method that eliminates some % of losers or obtain better odds. These days it quite easy to make money longterm as a 13% loss can be turned into a 2 to 5% profit, possibly even more, by obtaining better prices.

The loss on turnover quoted overall is using Tabcorp prices.