Table B-2e. Estimated Standard Errors for Shipment Characteristics by Total Modal Activity for the United States: Percent of Total for 2002, 1997, and 1993

Table B-2e. Estimated Standard Errors for Shipment Characteristics by Total Modal Activity for the United States: Percent of Total for 2002, 1997, and 1993

[Estimates are shown as percents and are based on data from the 2002, 1997, and 1993 Commodity Flow Surveys]

Excel | CSV

Mode of transportation Ton-miles (percent)
2002 1997 1993
Total
Truck 1.5 1.1 0.9
Rail 1.6 1.5 0.9
Shallow draft 0.6 0.4 1.0
Great Lakes 0.3 0.2 0.3
Deep draft 0.4 0.5 0.5
Air
Parcel, U.S.P.S. or courier
Pipeline S S S
Other and unknown modes 0.2 0.3 0.5

KEY:
– Represents data cell equal to zero or less than 1 unit of measure.
S Estimate does not meet publication standards because of high sampling variability or poor response quality.

NOTES: The Introduction and appendixes give information on confidentiality protection, sampling error, nonsampling error, sample design, and definitions. Links to this information on the Internet may be found at www.census.gov/cfs.

SOURCE: Bureau of Transportation Statistics (USDOT) and U.S. Census Bureau, 2002 Commodity Flow Survey, United States Data, December 2004.