Estimates are based on data from the 2007 Commodity Flow Survey. Because of rounding, estimates may not be additive.
|Percent||CV 2||Standard Error of %||CV||Standard Error of %||CV||Standard Error of %|
|Packing Group I||390,846||27||585,592||26.2||72,123||22.3||3.7||0.9||3.6||1.2||4.6||1.7|
KEY: - = Zero or Less than half the unit shown; thus, it has been rounded to zero.
1 Ton-miles estimates are based on
estimated distances traveled along a modeled transportation network.
2 Coefficient of Variation.
NOTES: Packing Groups I, II, and III reflect the level of hazard associated with the material being shipped. Packing Group I is the most rigorous. Value-of-shipment estimates are reported in current prices. Estimated measures of sampling variability for each estimate known as coefficients of variation (CV) are also provided in these tables. More information on sampling error, confidentiality protection, nonsampling error, sample design, and definitions may be found at http://www.bts.gov/publications/commodity_flow_survey/.
SOURCE: U.S. Department of Transportation, Research and Innovative Technology Administration, Bureau of Transportation Statistics and U.S. Department of Commerce, U.S. Census Bureau, 2007 Economic Census: Transportation Commodity Flow Survey, December 2009.