|Mode of Transportation||Value||Tons||Ton-miles|
|Parcel, U.S. Postal Service or Courier||2.9||0.6||0.1||-||0.1||-|
|Unknown and other modes||7.9||1.7||17.5||1.1||1.8||0.7|
KEY: - = less than 1 unit of measure or equal to zero; S = data are not published because of high sampling variability or other reasons.
a Truck as a single mode includes shipments that went by private truck only, for-hire truck only, or a combination of both.
b Private truck refers to a truck operated by a temporary or permanent employee of an establishment or the buyer/receiver of the shipment.
c Excludes most shipments of crude oil. See previous table for the estimated amount of crude oil and petroleum products transported in the United States.
NOTE: Numbers and percents may not add to totals due to rounding.
SOURCE: U.S. Department of Transportation, Bureau of Transportation Statistics, U.S. Department of Commerce, Census Bureau, 1997 Economic Census 1997 Commodity Flow Survey, Hazardous Materials (Washington, DC: December 1999), table 1.