Costa Mesa's local economy relies heavily on retail and services. The single largest center of commercial activity is South Coast Plaza, a shopping center noted for its architecture and size. The volume of sales generated by South Coast Plaza, on the strength of 322 stores, places it among the highest volume regional shopping centers in the nation. It generates more than one billion dollars per year. Some manufacturing activity also takes place in the city, mostly in the industrial, southwestern quarter, which is home to a number of electronics, pharmaceuticals and plastics firms. Business services company Experian is the largest employer in the city and has their North American Headquarters in Costa Mesa.