Backtest database


I have 45,949 total symbols available to backtest (includes delisted stocks). When I run the back test using all these symbols I get 17 winners, BUT when I run the backtest using the Russell 2000 (which is about 1,975 symbols) I get 26 winners. The question I have is that the 45,949 symbols include the Russell 2000 symbols so why am I getting more winners when I use the Russell 2000 stocks than when I use the total 45,949 symbols? Thank you!