The public shows significant concerns about rising health care costs, but there's a perception gap between experts and the public about what might be driving these costs. When asked to name the most urgent health problems in the U.S., Americans say cost and access. Six in 10 say they worry "a great deal" about the availability and affordability of health care today. Most health care experts point out advances in medical treatments, drugs and technology and the fact that people are living longer as reasons for the rise in health care costs. But while the public agrees that the aging population is a major factor, surveys show pluralities blame excess profits by drug and insurance companies, malpractice suits and fraud.