Odds based betting system - NHL

I did some research using MatchStatistics software and found out something interesting. I used a formula to test what results would had betting minimal of odds from specific range. It is surprising to me but betting lowest odds from range 4.35 – 4.70 was very profitable (from the beginning of 2008). I got following statistics only for NHL

Total number of bets: 982

Winning bets: 248

Average Odds: 4.47

Std. Dev. of Average Odds: 0,102216124534607

Average Winning Odds: 4.48

Std. Dev. of Average Winning Odds: 0,105875723063946

Average yield: 13%

Pessimistic average yield: 5%

Optimal Kelly's Fraction (OKF): 0,0377587415277958

Bankroll Multiplier for OKF: 10,5557537078857

That's how a total bankroll would have changed if one always wagered 3,78% of total bankroll

[URL=https://img339.imageshack.us/my.php?image=hockey.png][IMG]https://img339.imageshack.us/img339/7173/hockey.th.png[/IMG][/URL]

What do you think about that?. Is it possible that such tendency will continue? Does betting that is based on odds have sense anyway or maybe adding one's predictions to the system might make profit even better.