The statistics on skin cancer should make you grab the sun screen and a hat before you head outdoors, or perhaps cancel that appointment at the tanning salon.

The April issue of Mayo Clinic Health Letter covers the facts about the prevalence of skin cancer, including:

Half of all new cancers in the United States are skin cancers.

One in five Americans will develop skin cancer. Your chances of getting skin cancer double if you have had five or more sunburns.

The American Academy of Dermatology has labeled skin cancer an unrecognized epidemic.

Generally, your risk of developing skin cancer increases as you age because the effects of sun damage accumulate over time. Until recently, the more treatable non-melanoma skin cancers were considered a problem for people over age 50. However, the occurrence of these cancers in younger adults has increased sharply.

Mayo Clinic researchers have documented the increase by tracking skin cancer incidence in adults under age 40 in southern Minnesota. Between 1976 and 2003, the incidence of basal cell skin cancers - a non-melanoma skin cancer - roughly tripled in women, to more than 30 women per 100,000. The rate slightly increased among men, from about 23 to nearly 27 per 100,000.

Typically, 90 percent of non-melanoma cancers develop on sun-exposed skin such as the head and neck. In the Mayo Clinic study, only 60 percent of the cancers were found on sun-exposed skin, leading to the suspicion that visits to the tanning booth might account for those cancers.

When you head outdoors, slather on the sunscreen to block the sun’s ultraviolet radiation exposure. Use generous amounts - 1 ounce, or about the amount in a shot glass - to protect your skin from the sun’s rays. Apply sunscreen about 30 minutes before you go out and reapply every two hours. Wear protective clothing, a broad-brimmed hat and sunglasses.

As for tanning beds, think of them as high-dose UVA machines. They’re dangerous because occasional yet intense UVA exposure poses a greater risk of melanoma skin cancer than does spending long hours in the sun.