Estimates for time spent were derived using rating data for television and cable television, survey research for radio, mobile, out-of-home media and yellow pages, and consumer purchase data (units, admissions, access) for books, home video, in-flight entertainment, Internet, newspapers, magazines, box office, recorded music, video games.
Adults 18 and older were the basis for estimates for newspapers, consumer books, consumer magazines, in-flight entertainment, out-of-home media, yellow pages and home video.
Persons 12 and older were the basis for the estimates for box office, broadcast TV, cable TV Internet, mobile, radio recorded, music and video games. Source: Statistical Abstract of the United States/US Census Bureau
Related: 2008 Multimedia Audiences Summary