In the United States, charging an APR of 455 percent on a consumer credit card is virtually unheard of — and in some cases, would be illegal, said David Silberman, a senior fellow at the nonprofit Center for Responsible Lending. Twenty states plus D.C. set limits on the interest rates that payday lenders may charge; the highest of these is 36 percent, permitted by several states, according to the center. Lenders nationwide are barred from charging more than 36 percent to active-duty military service members and some of their family members. Federally chartered credit unions may not charge more than 28 percent. This legal patchwork has helped keep credit card rates in the United States under 30 percent. The average APR on new U.S. cards ranges from 20.7 percent to 24.6 percent — a 30-year high, according to WalletHub.