How common is the train tracks marking for het pieds?

[Brandon Osborne]

1/3 of my female hets actually has the "het pied markers".

All of my 100% hets have markers and the 50% and 66% animals also add up. So far, all possible , with markers, I have produced and kept track of have proven to be hets. Not all hets will have the "tracks" and as I've mentioned before, there is more to the marker than just the tracks. Some do not believe in the marker but I can say I do as well as a few "big name" breeders.