WASHINGTON — The Obama administration reported a significant deterioration in the financial outlook for Social Security on Monday, while stating that the financial condition of Medicare was stable but still unsustainable.

The Social Security trust fund will be exhausted in 2033, three years sooner than projected last year, the administration said. And Medicare’s hospital insurance trust fund will be depleted in 2024, the same as last year’s estimate, it said.

“The projections in this year’s report are somewhat more pessimistic than last year’s projections,” Treasury Secretary Timothy F. Geithner said in issuing the annual report on the two programs, which together account for more than 35 percent of all federal spending.

The central message of the new report was the same as in recent years: the two programs are unsustainable without structural changes that have so far eluded Congress and the administration.