Import cargo volume at the nation’s major retail container ports is expected to increase 3.2 percent in April compared with the same month last year, and year-over-year gains should continue through the end of summer, according to the monthly Global Port Tracker report released today by the National Retail Federation and Hackett Associates.

“Retailers are continuing to watch rising gas prices, but job gains and other indicators show the economy is strengthening,” NRF Vice President for Supply Chain and Customs Policy Jonathan Gold said. “All of this should improve consumer confidence and lead to increased spending, so retailers are cautiously building up their inventories.”

U.S. ports followed by Global Port Tracker handled 1.04 million Twenty-foot Equivalent Units in February, the latest month for which after-the-fact numbers are available. With February traditionally the slowest month of the year, that was down 16 percent from January and 5.7 percent from February 2011. One TEU is one 20-foot cargo container or its equivalent.

March was estimated at 1.19 million TEU, up 9.6 percent from a year ago, and April is forecast at 1.25 million TEU, up 3.2 percent from last year. May is forecast at 1.29 million TEU, the same as last year; June at 1.29 million TEU, up 3.6 percent; July at 1.35 million TEU, up 1.9 percent, and August at 1.42 million TEU, up 7.4 percent.

The first half of 2012 should total 7.3 million TEU, up 2.2 percent from the same period last year. The total for 2011 was 14.8 million TEU, up 0.4 percent from 2010’s 14.75 million TEU. NRF continues to project 2012 retail sales will grow 3.4 percent to $2.53 trillion.

“Our forecast for the remainder of the year has brought us back to the traditional peak season patterns,” Hackett Associates founder Ben Hackett said. “Hopefully the importers and the carriers can work closely together to ensure sufficient capacity and a solid supply chain.”