In November, the index gained 1.8 percent from its October level after falling for two straight months, according to the U.S. Department of Transportation's Bureau of Transportation Statistics.
The December level is a 2.9 percent rise over the recent low of 93.5 reached in May, when the index was at its lowest level since June 1997.
December's level is the lowest for the month since December 1996 when it was 89.1. From December 2008 to December 2009, the index fell 4.1 percent, the fourth largest annual decline in the 20 years for which the TSI is calculated.
The freight index is also down 13.2 percent in the five years from December 2004. In the 10 years from December 1999, the index is down 8.4 percent.
In the fourth quarter of 2009, the index was up 0.5 percent, the second straight quarterly boost after five consecutive quarterly declines that started from the second quarter of 2008.
The freight TSI measures the month-to-month changes in the output of services provided by the for-hire freight transportation industries. The index consists of data from for-hire trucking, rail, inland waterways, pipelines and air freight.
For additional historical data, visit www.bts.gov/xml/tsi/src/index.xml.