The average Medicare Part D premium will drop a bit in 2012, federal officials said today.

Premium costs for the prescription drug plan will be about $30, down slightly from the $30.76 paid out this year, U.S. Department of Health and Human Services officials said during an press conference.

Agency Secretary Kathleen Sebelius said the Affordable Care Act, passed last year, was responsible for much of the savings. The program benefits from competition between private insurance plans and increased use of generic medicines.

Moreover, nearly 900,000 Medicare patients who fell into the so-called "donut hole," where costs aren't covered, have received a 50% discount on their prescription medicines this year, officials said. Such patients saved more than $200 million in June alone.

Similarly, more than 17 million Medicare patients have taken advantage of free annual wellness visits and preventative health screens for such diseases as colon and breast cancer.

Browse Our Free Senior Care Guides

Medicare covers about 47 million people. About half rely on Part D for their prescription drugs.

Recent studies have shown that the drug benefit has saved the government an average of $1,200 a year in reduced hospital and nursing home costs for each participant who did not have adequate prescription drug coverage before the program began in 2006, and that without the plan, seniors would cut back on medications or be less likely to have their prescriptions filled.