Chain-type Index: 2000 = 100 (Yearly average based)
Notes: 2007 data are through July. May-July 2007 data are preliminary. The TSI total is a single index measure of monthly output of for-hire transportation services in the United States using 2000 as the base year.
Source: Compiled by U.S. Department of Transportation, Research and Innovative Technology AdministrationBureau of Transportation Statistics (BTS), special calculation, September 2007, avaliable at: http://www.bts.gov/xml/tsi/src/index.xml.