Many cultures produce food for sale in restaurants for paying customers. These restaurants often have trained chefs who prepare the food, while trained waitstaff serve the customers. The term restaurant is credited to the French from the 19th century, as it relates to the restorative nature of the bouillons that were once served in them. However, the concept pre-dates the naming of these establishments, as evidence suggests commercial food preparation may have existed during the age of the city of Pompeii, as well as an urban sales of prepared foods in China during the Song Dynasty. The coffee shops or cafes of 17th century Europe may also be considered an early version of the restaurant.[25] In 2005 the United States spent $496 billion annually for out-of-home dining. Expenditures by type of out-of-home dining was as follows, 40% in full-service restaurants, 37.2% in limited service restaurants (fast food), 6.6% in schools or colleges, 5.4% in bars and vending machines, 4.7% in hotels and motels, 4.0% in recreational places, and 2.2% in other which includes military bases.[26]