Food Outbreaks Declining

Alex Tabarrok says that despite the recent headlines, the quantity of foodborne-disease outbreaks is actually on the decline of the past ten years. This strikes me as a pretty small and noisy data series to be drawing a trend line through if we don't know whether the decline continued through 2007 and 2008, but that does seem to be the trend on hand. At the same time, isn't the pattern of spiking in even years and declining in odd years sort of strange.