Figure 5-5 Detrended Passenger TSI, Detrended and Smoothed Passenger TSI and Growth Cycles: January 1979–December 2013
NOTES: Shaded areas indicate economic recessions (business cycles). Detrending and smoothing refer to a statistical procedure that makes it easier to observe changes in upturns and downturns of the data. Detrending removes the long term growth trend and smoothing eliminates month to month volatility.
SOURCE: U.S. Department of Transportation, Bureau of Transportation Statistics, Transportation Services Index and the Economy Revisited, Decem- ber 2014, available at www.bts.gov as of December 2014.