Total: 17 (12 Democrats and 5 Republicans)

As of January 2011

Democrats
Boxer, Barbara -- CA
Cantwell, Maria -- WA
Feinstein, Dianne - CA

Gillibrand, Kirsten -- NY

Hagan, Kay -- NC
Klobuchar, Amy -- MN

Landrieu, Mary - LA
McCaskill, Claire -- MO
Mikulski, Barbara - MD
Murray, Patty - WA

Shaheen, Jeanne -- NH
Stabenow, Debbie -MI

Republicans

Ayotte, Kelly -- NH
Collins, Susan - ME
Hutchison, Kay Bailey - TX
Murkowski, Lisa -AK
Snowe, Olympia --ME