WASHINGTON — The Obama administration said Friday that the federal budget deficit for the fiscal year that just ended was $1.4 trillion, nearly a trillion dollars greater than the year before and the largest shortfall relative to the size of the economy since 1945.

The number, while lower than forecast a few months ago, underscored the challenges ahead in shrinking the deficit even as the White House and Congress are considering more steps to stimulate an economy that is making a slow recovery. The political hurdles to finding a solution were evident on Friday as each political party immediately blamed the other for the growth of the deficit.

The shortfall for the fiscal year 2009, which ended Sept. 30, translates to 10 percent of the economy, according to a joint...