Scottrade, Inc. $3\mathrm{.}43\mathrm{.}43\mathrm{.}5$

Charles Schwab $3\mathrm{.}23\mathrm{.}33\mathrm{.}4$

Fidelity Brokerage Services $3\mathrm{.}13\mathrm{.}43\mathrm{.}9$

TD Ameritrade $2\mathrm{.}93\mathrm{.}63\mathrm{.}7$

E$*$Trade Financial $2\mathrm{.}93\mathrm{.}22\mathrm{.}9$

$($Not listed$)2\mathrm{.}53\mathrm{.}22\mathrm{.}7$

Vanguard Brokerage Services $2\mathrm{.}63\mathrm{.}82\mathrm{.}8$

USAA Brokerage Services $2\mathrm{.}43\mathrm{.}83\mathrm{.}6$

Thinkorswim $2\mathrm{.}62\mathrm{.}62\mathrm{.}6$

Wells Fargo Investments $2\mathrm{.}32\mathrm{.}72\mathrm{.}3$

Interactive Brokers $3\mathrm{.}74\mathrm{.}04\mathrm{.}0$

Zecco.com $2\mathrm{.}52\mathrm{.}52\mathrm{.}5$

Firstrade Securities $3\mathrm{.}03\mathrm{.}04\mathrm{.}0$

Banc of America Investment Services $4\mathrm{.}01\mathrm{.}02\mathrm{.}0$ What is the coefficient of determination?