The figures above are for both Metro and Country.
I've found that doing the figures on favourites is more reliable and not prone to other factors, the longer the price, the less reliable the stats are.
But to satisfy curiosity, let's take all prices, not just favourites:
All Runners: 9.50% S/R
First Starters: 7.34% S/R
First Uppers: 8.62% S/R
Second Run: 8.78% S/R
Third Run: 9.93% S/R
Fourth Run: 10.41% S/R
Fifth Run: 10.73% S/R
Greater than five runs: 9.90% S/R
But I stress, the favourite figures are much more reliable, taking all horses includes way too many hazard factors.
I've also busted a couple of other myths along the way:
"odds on, look on"
and
"Don't bet on heavy tracks"
I have a feeling that many of these myths were never based on facts and figures, but rather emotion. When it goes wrong, punters will look for a reason and it gets etched into the memory as fact, but it may be a biased reason that is based on the memory's sample size.