WASHINGTON (Reuters) - U.S. Treasury Secretary Janet Yellen said on Thursday that President Joe Biden’s fiscal 2022 budget request will increase the U.S. federal debt-to-GDP ratio above its current level of about 100% over the next decade. But Yellen told a U.S. House of Representatives Appropriations subcommittee that Biden’s budget plans were fiscally responsible, partly because the real interest burden to finance the federal debt is currently negative because long-term Treasury yields of 1.6% are below a 2% inflation rate. “We’ll have a temporary period of spending too and some of these increases, will - beyond the budget window - will result in lower deficits and more tax revenue to support those expenditures. I believe it is a fiscally responsible program,” Yellen said. Reporting by David Lawder; Editing by Chris Reese Our Standards: The Thomson Reuters Trust Principles.