According to the File, 39% of the incidents in 2011 involving shark teeth sinking into unwitting human flesh occurred in shallow waters off U.S. beaches. That's way more than Australia, who racked up 14% of shark attacks last year to come in second. And yet, the United States' share of incidents was the lowest in over a decade-between 2001 and 2011, an average of 59% of confirmed, unprovoked attacks took place in U.S. waters.

Apparently, this trend doesn't have anything to do with the relative deliciousness of American thigh meat. According to an analysis by George Burgess, a shark researcher at the Florida Museum of Natural History and the current keeper of the International Attack File, "the number of shark-human interactions occurring in a given year directly correlates with the amount of time humans spent in the sea."

And that simple fact could explain why attacks in the U.S. have been on the decline. Americans have likely spent less time in the water since the recession, writes Burgess, limiting their exposure. That might not be the whole story, however; Burgess thinks that worldwide overfishing could also mean there are fewer animals out there mistaking a wetsuited human for a savory seal.