United States Cellular Corporation (U.S. Cellular) provides wireless service to approximately 6.1 million customers in five geographic market areas in 26 states as of December 31, 2007. During the year ended December 31, 2007, U.S. Cellular owned interests in 218 consolidated wireless markets, which covered portions of 34 states and a total population of 82.4 million. The 218 consolidated markets included 183 operating markets, or markets in which U.S. Cellular provides wireless services to customers, covering 26 states and a total population of 44.9 million. U.S. Cellular operated approximately 6,400 cell sites, had over 400 U.S. Cellular operated retail stores and had relationships with agents, dealers and non-Company retailers that aggregated over 1,300 locations. The Company's main sources of revenues are from its own customers and from inbound roaming customers.