ARLINGTON, VA — Talk about a jump. The American Trucking Associations’ (ATA) seasonally adjusted for-hire truck tonnage index for 2011 jumped 5.9 percent over 2010, making 2011 the largest annual increase since 1998.

After a 0.3 percent increase in November, tonnage in December 2011 was up 6.8 percent not to mention 10.5 percent higher than December 2010 — the largest year-over-year gain since July 1998.

“While I’m not surprised that tonnage increased in December, I am surprised at the magnitude of the gain,” ATA Chief Economist Bob Costello said. Costello noted that it was the largest month-to-month increase since January 2005.

“Not only did truck tonnage increase due to solid manufacturing output in December, but also from some likely inventory restocking. Inventories, especially at the retail level, are exceedingly lean, and I suspect that tonnage was higher than expected as the supply chain did some restocking during the month.” he said.

The not seasonally adjusted index, which represents the change in tonnage actually hauled by the fleets before any seasonal adjustment, equaled 116.4 in December, which was 0.8% above the previous month.