WASHINGTON –

With beach season in full swing, the question inevitably arises: What are the chances of getting attacked by a shark?

In a phrase: extraordinarily low — though not nonexistent. It is higher in certain parts of the U.S. (Florida tops the list) than in others, and in some places (off Cape Cod) legendary great whites are making a comeback that can be frightening to beachgoers. But is it really worth worrying about a shark strike or considering forgoing an ocean swim as an act of self-preservation?

Let's consider the numbers, courtesy of the International Shark Attack File at the Florida Museum of Natural History. Last year, 80 unprovoked shark strikes took place worldwide: Seven resulted in deaths, including one in California. Fifty-three strikes took place in U.S. waters, nearly half of them off Florida.

According to the file's analysis of 2000 data, beachgoers faced a 1-in-2-million chance of dying from drowning and other causes based on visits to East and West Coast beaches. By contrast, they faced a 1-in-11.5-million chance of being attacked by a shark, and less than a 1-in-264-million chance of dying from a shark bite, since just one person died that year in U.S. waters from an attack.

Put another way, more Americans were killed by collapsing sinkholes (16) than sharks (11) between 1990 and 2006, and more by tornadoes (125) than sharks (6) in Florida between 1985 and 2010.

"Tides and currents kill more people (at the beach) than sharks that kill people," said Gregory Skomal, a shark biologist with Massachusetts Division of Marine Fisheries.

But in some parts of the country, the number of shark spottings has risen in recent years. Last year, there were more than 20 confirmed shark sightings at Cape Cod beaches, in areas including its outer beaches and off the mainland, and a 50-year-old man was bitten by a shark that scientists believe was a great white. (The swimmer, a Colorado native, was scarred but survived with limbs intact.)

This summer, eight great whites already have been spotted off various Cape Cod beaches, though some of the sightings may involve the same shark. The National Park Service just issued precautionary guidelines for Cape Cod swimmers.

Skomal has been tracking great whites off Cape Cod for years: He and his colleagues tagged five in 2009 and 17 in 2012. The probable reason for the increase is a resurgence in the seal population, which has been recovering over the past four decades since enactment of the Marine Mammal Protection Act, which outlawed a kind of hunting that caused the seals' precipitous decline. The National Oceanic and Atmospheric Administration estimates that the seal population in the western North Atlantic has increased by tens of thousands over the past few decades.

A spate of shark strikes in 2001 that claimed the lives of swimmers — including two in the mid-Atlantic, 10-year-old David Peltier off Virginia Beach and 28-year-old Sergei Zaloukaev off Cape Hatteras, North Carolina — earned the season the nickname "Summer of the Shark." Zaloukaev was the last person to die from a shark bite in the mid-Atlantic.

Still, there have been nonlethal events. Last month, 63-year-old surf instructor Barbara Corey was bitten off Holden Beach in Brunswick County, North Carolina, the first mid-Atlantic shark strike this year. Last year, there were two, both in North Carolina, where 6-year-old Brooklyn Daniel was struck off Brunswick and 33-year-old Megan Konkler was bitten off Nags Head Beach.

Common-sense precautions — avoiding areas where seals congregate, staying close to shore and staying out of the water around dawn and dusk, when sharks tend to be feeding and water visibility is low — are the best ways to avoid coming into a contact with a shark, experts say.

The shark species that pose the greatest risks to humans are great white, tiger, bull and oceanic whitetip sharks. So the regions of the world where some of these sharks swim — including Australia, South Africa and California, where great whites regularly migrate — tend to have more fatalities. Of the seven fatalities last year, according to the International Shark Attack File, three were off South Africa, two of Australia, one off California and one off the French island of Reunion in the Indian Ocean. Despite its small size, Reunion has emerged as one of the world's deadliest shark sites: a 15-year-old was killed July 15 off a beach where swimming was prohibited, the second Reunion death this year and the fifth since 2011.

Scientists do not know why this number is so high, but George Burgess, director of the International Shark Attack File, said he suspects human factors are playing a role. Island residents have cut back on shark fishing because of concerns over the toxins in shark meat; Burgess said an increase in global tourism means more people who are not familiar with the island are visiting and swimming there. "Now you've got a great rush of people in the water who don't know the area, and don't know the risks." he said.

Christopher Neff, a doctoral candidate at the University of Sydney who researches the human-shark relationship, wrote in an email that humans are becoming more open to protecting sharks in the open ocean even as they're growing more hostile to those near shore. In March, the Convention on International Trade in Endangered Species of Wild Flora and Fauna agreed to impose new rules on the trade in hammerhead, oceanic whitetip and porbeagle sharks under which countries would have to prove their catch was sustainable before exporting these fish.

In December, French Polynesia and the Cook Islands joined together to create the world's largest shark sanctuary, emulating small island nations such as Palau and the Maldives in banning all shark fishing in their waters.

But both western Australia and Reunion have authorized shark hunts in the wake of deadly strikes there. Neff noted that researchers have become better at tracking sharks' swimming patterns with the use of satellite and radio tagging, but sharing this sort of information "can arouse public anxiety," and it can't prevent some of the inevitable human-shark interactions that arise.

"Anywhere we have a beach, we likely have sharks," he wrote. "The difference is that until now, we didn't know it."