Index: 1955 = 100
NOTE: Output is measured by quality-adjusted ton- and passenger-miles for railroad and air transportation, quality-adjusted ton-miles for trucking and pipelines, and passenger-miles for buses. Quality-adjusted refers to differences in services and handling, e.g., the difference between flying first class and coach or differences in the handling requirements and revenue generation of high- and low-value commodities. No data are available for water transportation. Most recent data available are provided.
SOURCE: U.S. Department of Labor, Bureau of Labor Statistics, Office of Productivity and Technology, available at http://www.bls.gov/lpc/iprdata1.htm, as of May 2001.