Projected costs of Medicare’s a prescription drug benefit are $117 billion lower than previously estimated, according to a statement from the Centers for Medicare & Medicaid Services. Costs over the next 10 years will be lower, CMS says, because of slowing drug cost trends, lower estimates of plan spending and higher-than-expected rebates from drug manufacturers.

Enrollment in Medicare programs is up, as well. According to officials, there were 4 million calls to 1-800-MEDICARE during the open enrollment period from Nov. 15 and Dec. 31 – 11% more than the same period in 2006. Online registration also was up by 49%, to more than half a million enrollees.

Roughly 90% of Medicare beneficiaries get their drug coverage from Medicare, former employers or other sources, officials said. More than 25 million people are now enrolled in Part D, and 85% of them have expressed satisfaction with the program, officials said.