Despite the media hype, the fact is that sharks do not target humans as the source of a good meal. Occasionally, sharks do mistake humans for their usual food or feel threatened and react to protect themselves, but such incidents are extremely rare.

According to the International Shark Attack File (ISAF), in 2006, there were 62 confirmed cases of unprovoked shark attacks on humans worldwide. Of these attacks, 4 proved to be fatal. In that same year, there were 39 attacks and no fatalities in the United States.

You have a better chance of dying by a lightning strike, or a dog bite. More children are killed while playing in a beach sand hole that collapses or while being inadvertently left in a closed car on a hot day, than there are people killed by a shark attack. A recent New York Times article sums it up pretty well by saying you have double the chance of dying from a coconut falling on your head.

Sources:
Shark attacks and fatalities: International Shark Attack File
Collapsing sand holes: Dr. Bradley Maron, The New England Journal of Medicine (June 2007)
Dog attack statistics: National Canine Research Foundation
Child hyperthermia: Hyperthermia Deaths of Children in Vehicles , Jan Null, Adjunct Professor of Meteorology, San Francisco State University, October 31, 2007
Lightning data: National Oceanic and Atmospheric Administration’s National Weather Service
Hunting incidents data: International Hunter Education Association
Bicycle fatalities data: NHTSA Fatality Analysis Reporting System