The rate at which these events occurred went from approximately 1 every other month between 2000 and 2008 (5 per year) to more than 1 per month between 2009 and 2012 (almost 16 per year). The authors’ tracking also indicates that this increased rate has continued into 2013—more specifically, there were 15 events. While it is possible that this increase is an artifact of the search strategy (perhaps, archiving of the news reports has improved in recent years), the authors believe that the observed rise represents a real increase in the number of events in recent years.