The overall consumer price index in the Treasure Valley dropped by 2.2 percent in November, according to Wells Fargo, which tracks it. That exceeded the national CPI drop for the month of 1.9 percent (or 1.7 percent seasonally adjusted). That national seasonally adjusted figure was the largest drop in CPI since the U.S. Department of Labor began reporting the figures in 1947. "The drastic decrease in energy costs coupled with slow retail sales have brought concerns of deflation in future months to the forefront," reports Cicero Research, which analyzes consumer price data for Wells Fargo. "The U.S. could be entering a deflationary period which may last into early next year depending on how quickly the influx in liquidity, via the congressional bailout and the actions of the Federal Reserve, takes effect."