The year is expected to end with a 2.4 percent increase over 2012.

“As the economy continues to slowly improve, retailers are stocking up for their most important sales season of the year,” NRF Vice President for Supply Chain and Customs Policy Jonathan Gold said. “Merchants have been very cautious so far this year, but our forecasts show that they plan to make up for it in the next few months.”

Cargo import numbers do not correlate directly with retail sales or employment because they count only the number of cargo containers brought into the country, not the value of the merchandise inside them. But the amount of merchandise imported nonetheless provides a rough barometer of retailers’ expectations.

U.S. ports followed by Global Port Tracker have seen year-over-year declines in cargo every month since March with the exception of May, which saw a 1.6 percent increase. In June, the latest month for which after-the-fact numbers are available, the ports handled 1.36 million Twenty-foot Equivalent Units, down 2.7 percent from May and 1.8 percent from June 2012. July was estimated at 1.4 million TEU, down 0.6 percent from a year ago. One TEU is one 20-foot cargo container or its equivalent.

But the trend is expected to change in August, which is forecast at 1.45 million TEU, up 1.7 percent from last year. September is forecast at 1.43 million TEU, up 1.9 percent; October at 1.45 million TEU, up 8.3 percent; November at 1.37 million TEU, up 6.7 percent; and December at 1.34 million TEU, up 3.5 percent.

Those numbers would bring 2013 to a total of 16.2 million TEU, up 2.4 percent from 2012’s 15.8 million TEU. The first six months of 2013 totaled 7.8 million TEU, up 1.2 percent from the first half of 2012.

“Trade at the ports continues to remain positive, confirming our view that the economy remains on a slow but steady course of recovery,” Hackett Associates Founder Ben Hackett said. “The question is whether importers are building up stock ahead of expected sales demand or in response to recently announced freight rate increases.”

Global Port Tracker, which is produced for NRF by the consulting firm Hackett Associates, covers the U.S. ports of Los Angeles/Long Beach, Oakland, Seattle and Tacoma on the West Coast; New York/New Jersey, Hampton Roads, Charleston, Savannah, Port Everglades and Miami on the East Coast, and Houston on the Gulf Coast.

National Retail Federation