|Number ($ millions)||Percent||Number (thousands)||Percent||Number (millions)||Percent|
|Air (including truck and air)||450||6.8||43||0.2||34||0.5|
|Parcel, U.S. Postal Service, or courier service||237||3.6||11||Z||9||0.1|
|Truck and rail intermodal combination||S||S||S||S||S||S|
|Truck and water||196||2.9||63||0.3||65||0.9|
|Rail and water||Z||Z||Z||Z||Z||Z|
|Other multiple modes||Z||Z||Z||Z||Z||Z|
|Other and unknown modes||584||8.8||3,435||17.5||409||5.8|
KEY: S = data do not meet publication standards because of high sampling variability or other reasons; Z = zero or less than 1 unit of measure.
NOTE: The Commodity Flow Survey covers business establishments in mining, manufacturing, wholesale trade, and selected retail industries. The survey also covers selected auxiliary establishments (e.g., warehouses) of in-scope multiunit and retail companies. The survey excludes establishments classified as farms, forestry, fisheries, governments, construction, transportation, foreign establishments, services, and most establishments in retail. Due to industry-wide reporting problems, shipments by oil and gas extraction establishments are also excluded.
SOURCE: U.S. Department of Transportation, Bureau of Transportation Statistics and U.S. Department of Commerce, U.S. Census Bureau, 1997 Commodity Flow Survey: United States, Washington, DC: 1999, available at http://www.bts.gov/ntda/cfs/cfs97od.html as of Nov. 2, 2001.