U.S. central bank officials raised the key U.S. interest rate slightly Wednesday and said further increases will come at a "gradual" pace. The quarter of a percentage point increase (to a range between half- and three-quarters-of-one-percent) is still low by historic standards. It is the first rate increase in a year. During the recession, the U.S. Federal Reserve slashed the rates nearly to zero to boost economic growth by making it cheaper to borrow money needed to buy homes, build factories and hire people. Economists say the U.S. job market and housing sector have largely recovered from the recession and no longer need so much help. Experts say keeping interest rates too low for too long leaves the Fed without the tools it needs to bolster the economy when the next downturn hits. It also raises the risk of sparking strong inflation that could hurt the economy. The Fed now appears likely to boost rates a couple more times over the next year. Meanwhile, a report from the Committee for a Responsible Federal Budget says higher interest rates will increase the cost of repaying the huge U.S. government debt. CRFB says interest on the debt is the fastest growing part of Washington's budget, and boosting interest rates by one percent could add $1.5 Trillion to the debt over a decade.