In December, BLS says, prices were unchanged.
One major reason inflation slowed last year: Gas prices went up just 1.7 percent, after gains of 13.8 percent in 2010 and 9.9 percent in 2011. Also, food costs rose 1.8 percent. BLS says that was "a deceleration" from the 4.7 percent increase in 2011.
As Reuters writes, the news that inflation remains in check "should help give the Federal Reserve room to prop up the economy by staying on its ultra-easy monetary policy path." In other words, there's no reason to think the Fed will need to start pushing up short-term interest rates anytime soon.