Wherever possible, ATA data reflects the entire U.S. airline industry as defined by the Department of Transportation. U.S. airlines transport beween 30-35 percent of global passenger and cargo traffic (revenue ton kilometers). In 2008, U.S. passenger and cargo airlines enplaned 741.4 million passengers (averaging 2.03 million per day) in scheduled service and nearly 18.1 million tons of cargo (averaging 49,500 tons per day) in scheduled and nonscheduled services on more than 11 million flights. Where industrywide data is not available on a timely basis, ATA uses sample groups to approximate industry trends or refers visitors to data from the appropriate government agencies.