For central banks around the world, the most informative piece of economic data released anywhere this week was the news that Swedish consumer prices fell 0.4 percent in September from a year earlier. The seventh monthly decline of the year leaves the Riksbank dicing with deflation. The world’s oldest central bank has already undershot its 2 percent inflation target for almost three years, and is now poised to respond by the end of this month by cutting its benchmark repo rate from a record low of 0.25 percent.