to be honest i dont track it everyday, but on random days i'd go and see what the spread or ML for a game should be and whenever i check it always gets it right.
but i doubt it hits a good % or else everyone would just use that. and it's so popular as you said that books would all be under if it worked long term.
the green star games i recall a thread about it a while ago, i believe it was stated that it was very hot for a while, and that they EXPECTED it to eventually cool down and hit 50% again, although i dont recall anyone tracking every game daily.
this site has all the Green star edge games for a given day based on statfoxes data.
http://www.sportsbook.com/statfeed/i...top-powerlines.
It just makes it easier to see them all if you plan to track.