WASHINGTON — The Congressional Budget Office predicted on Tuesday that the United States deficit will top $1 trillion annually over the next 10 years, ultimately reaching $1.7 trillion in 2030.

The ballooning deficit is being fueled by increased borrowing by the federal government, which continues to spend more money than it takes in. By 2030, the C.B.O. projected, federal debt held by the public will surpass $31 trillion — about 98 percent of the forecast size of the nation’s economy.

The federal budget deficit already hit $1 trillion last year — the first calendar year since 2012 that the gap between revenue and spending topped the trillion-dollar mark. The C.B.O.’s projections suggested that would become a permanent pattern over the next 10 years.

The somber news was tempered somewhat by the budget office’s expectation that interest rates for the next decade would be substantially lower than what its August forecast indicated, saving the United States hundreds of billions of dollars in interest payments on the federal debt.