AARP, formally the American Association of Retired Persons, is an American based interest group. It was established in 1958 by Ethel Percy Andrus, a retired educator from California, and Leonard Davis. Davis would later go on to found the Colonial Penn Group of insurance companies. AARP is a large and venerable interest group concentrating on problems faced by Americans aged 50 or older. With close to 38 million participants, AARP is one of the most potent interest groups in the States. The organisation lobbies on issues like Social Security, Medicare, and prescription drug prices. In more recent years, AARP has also staked positions on problems such as climate change and age discrimination. The non-profit organisation is mainly based in Washington, D.C., and is funded by members through dues and donations. AARP also offers a number of discounts and advantages to members, such as insurance, travel, and financial advantages.