|Mode of Transportation||Value ($ million)||Percent||Tons (thousands)||Percent||Ton-miles (millions)||Percent|
|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|
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.
KEY: S = Data are not published because of high sampling variability or other reasons; -- less than 1 unit of measure or equal to zero.
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.