What percent of light skinned red heads get skin cancer, compared to the average u.S. Population?

Red heads. Red hair is one of the risk factors that is a increased risk of melanoma over black or brown hair. Such risk factors are related to the genetics that red headed people are more likely to be fair skinned and their skin burns more easily than others. People with such risk factors (also many moles, northern europe decent (e.g. Fair skin), blue eyes, family history of melanoma) means that they should.
Higher than normal. Although there is likely no universal percentage of skn cancer in a population, fair skinned people are the most prone group, and there have been many seperate studies showing this. This has to do with ultraviolet light exposure, and not enough pigment protection. All forms (melanoma, basal cell, squamous cell) are higher in this group. Use of sunscreen, and less exposure helps lower risk.