The first two comments inspired me to add some information.
Average number of people killed by sharks worldwide every year: 4
Average number of people killed in car accidents worldwide every year: 1.2 millions
Average number of people killed by DOGS IN THE USA ONLY every year: 26
In contrast we are killing close to 100 million sharks per year and most of them are simply killed for their fins to make shark fin soup, a status symbol in China. Next time you go into a chinese restaurant and you see shark fin soup on the menu remember an animal that has almost the same life span as you died for that soup and his fins were severed from his body and the body dumped over the side.
Virtually all the shark attacks happened because the shark thought the victim was either a seal (in the case of a surfer think how a surfer looks from below) or there was poor visibility in shallow water. Virtually all attacks are a single bite and the shark didn't come back for more because it didn't taste like he expected. The deaths are usually due to blood loss.
For more info on shark attacks and the number of sharks killed by humans go to: