NOTES: At the time of this publication the Bureau of Economic Analysis (BEA) had only published chained 2009 dollar estimates from 1997 onward. Current dollar estimates for earlier years can be found in table 3-1, and chained 2005 dollars estimates for earlier years can be found in the 2013 edition of NTS, table 3-2. Chained (2009) dollar series are calculated as the product of the chain-type quantity index and the 2009 current-dollar value of the corresponding series, divided by 100. Because the formula for the chain-type quantity indexes uses weights of more than one period, the corresponding chained-dollar estimates are usually not additive.
SOURCE: U.S. Department of Commerce, Bureau of Economic Analysis, Industry Economic Accounts, Interactive tables, available at http://www.bea.gov/industry/index.htm as of September 2014 as cited in the U.S. Department of Transportation, Bureau of Transportation Statistics, National Transportation Statistics. Available at http://www.bts.gov as of June 2015.