Starting Sept. 23, health insurers must file annual reports that summarize what percentage of customers' premiums went to pay medical bills. Health insurers who pay out less than 80% of the premiums they collect from people who either buy their own insurance or receive it from small employers will have to provide rebates next year. That's just one example of the pending changes under federal health care reform that will remake the market for health insurance. The biggest changes could come in the market for individuals and families who don't get health benefits through an employer. The state has allowed competition to regulate the market. The real driver in health insurance premiums is health care spending, and Wisconsin has a competitive insurance market compared to some states. Yet, how health insurers determine rates leaves most consumers flummoxed and frustrated, particularly those who buy insurance on their own.