Marilyn Tavenner, the administrator of the Centers for Medicare and Medicaid Services, pauses while testifying on Capitol Hill in Washington, Tuesday, Oct. 29, 2013,  before the House Ways and Means Committee hearing on the implementation of the Affordable Care Act. Stressing that improvements are happening daily, the senior Obama official closest to the administration's malfunctioning health care website apologized Tuesday for problems that have kept Americans from successfully signing up for coverage. (AP Photo/J. Scott Applewhite)

Photo by: J. Scott Applewhite

Marilyn Tavenner, the administrator of the Centers for Medicare and Medicaid Services, pauses while testifying on Capitol Hill in Washington, Tuesday, Oct. 29, 2013, before the House Ways and Means Committee hearing on the implementation of the Affordable Care Act. Stressing that improvements are happening daily, the senior Obama official closest to the administration's malfunctioning health care website apologized Tuesday for problems that have kept Americans from successfully signing up for coverage. (AP Photo/J. Scott Applewhite)