The U.S. government-subsidized prescription plan will cost seniors an average 30 U.S. dollars a month in 2012, down from 30.76 dollars this year, according to media reports on Monday. Even as health costs continue to rise, medicare beneficiaries will see the average price of a Part D drug plan decline slightly next year, some relief amid pressure to cut the federal health insurance program for the elderly. The Part D drug benefit, created under the George W. Bush administration, allows seniors and others on Medicare to sign up for a privately administered, government-subsidized health plan to get their prescriptions. Popular with beneficiaries, the program has also proven far less costly than budget analysts originally expected, in part because of competition among private plans and the growing use of less expensive generic drugs.