The most common properties are condominium or hotel styles. Timeshare are created by resort developers who divide the units into equal time intervals. The divide units are marketed and sold to buyers who purchase a specific time of year to occupy the resort. The buyers own an equal share of the condominium unit and common ground which includes the resort accommodations. ARDA (American Resort Development Association) Based in Washington, D.C., this is the foremost trade association representing the timeshare ownership and property development industries. ARDA advocates on behalf of resort owners and developers and also lobbies for the industry. ARDA was first known as the American Land Development Association, originally founded in 1969. Today, ARDA is comprised of nearly one thousand small companies and large conglomerates from all over the world.