J.D. Power and Associates has released its latest Online Investor Satisfactioin Study ranking online investing firms, showing that Scottrade, Vanguard, Fidelity Investments, Sharebuilder, and Charles Schwab lead the industry in customer satisfaction. The study also showed that the average number of annual trades performed by investors is 36, up from 2004 and 22 in 2003. The study included responses from 5,099 online investors and included 19 firms.