13.77 U.S. air carrier traffic.
Consider monthly total number of passenger miles on U.S. domestic flights from the previous exercise.
airtrav
13.77
(a) 0.888, 0.833, 1.050, 0.995, 1.038, 1.098, 1.152, 1.108, 0.931, 0.995, 0.937, 0.966. (b) The seasonally adjusted series increases over time and is quite stable. (c) . The trend term is significant, . (d) For June 2014: 54,037,215.