NOAA's National Weather Service kicked off this year's National Lightning Safety week with the release of a new study on lighting deaths in the U.S. From 2006 through 2012, 238 people were struck and killed by lightning, with two thirds of the fatalities occurring during leisure activities. Fishing tops the list of activities, accounting for 26 deaths -- more than three times as many as golfing.

Most people killed during leisure activities were participating in water-related pastimes, including fishing, boating, swimming and simply spending time by a lake or on the beach. Sports contributed to 19 percent of the fatalities during leisure activities, with 12 people killed while playing soccer and eight while golfing.

"When people think of lightning deaths, they usually think of golf,"said John Jensenius, the NWS lightning safety specialist who conducted the study. "NOAA has made a concerted effort to raise lightning awareness in the golf community since we began the campaign in 2001, and we believe our outreach has made a huge difference since lightning-related deaths on golf courses have decreased by 75 percent."

According to Jensenius, water-related deaths may be more common because participants require more time to find shelter in a storm. "People often wait far too long to head to safety when a storm is approaching, and that puts them in a dangerous and potentially deadly situation," he said.

During the seven-year study, 82 percent of those killed by lightning were male and most victims were between the ages of 10 and 60. About 70 percent of the deaths occurred during June, July and August.

So far this year, seven people have been killed by lightning. Three of them were killed while fishing and a fourth was walking on the beach.