Ten of the past year's unprovoked attacks were fatal, up from five the year before, with a disproportionate number occurring in Australia. Although the country accounted for 22% of all attacks, it made up 40% of fatalities.

There were also two confirmed deaths in the U.S., and one each in the Bahamas, Egypt, Mexico and New Caledonia. Other confirmed, non-fatal bites occurred in Costa Rica, Colombia, Brazil, New Zealand, Seychelles, Turks and Caicos, Ecuador (in The Galápagos Islands) and South Africa.

"This is within the range of the normal number of bites, though the fatalities are a bit unnerving this year," said Gavin Naylor, director of the Florida Museum of Natural History's shark research program.

The United States had 36 unprovoked attacks, accounting for 52% of incidents worldwide. Of these, two—one in California and another in Hawaii—were fatal. As in previous years, Florida had more shark bites than any other state, with 16 attacks.

While ISAF documents and investigates all bites on humans by sharks, the annual report focuses primarily on unprovoked attacks. These are defined as any instance in which a shark is in its natural habitat and attacks without any human provocation, which includes intentionally approaching a shark or swimming in an area where bait is being used to lure fish. Unprovoked bites are the most useful for studying how sharks behave.