With retail sales predicted to inch up around 4 percent this year, cargo container traffic should also see healthy growth.

According to the “Global Port Tracker” report released on April 10 by the National Retail Federation, the nation’s major ports should be pretty busy this spring and summer as the economy improves and shoppers won’t be shy about making purchases.

“Consumers are spending more, and these import numbers show that retailers expect that to continue for a significant period,” said Jonathan Gold, the NRF’s vice president for supply chain and customs policy. “This is a clear sign that the economy has long-term momentum regardless of month-to-month fluctuations.”

Ben Hackett, the founder of Hackett Associates, which prepares the monthly NRF report, said his surveys show that cargo container volumes coming into the United States will remain stable despite the uncertainties with the new Trump administration’s threats to change trade policies and curtail imports. “Despite pre-election promises, there has been little real change in trade policy so far and little change is expected for the greater part of the year,” Hackett said.

For the first half of 2017, cargo container imports are expected to rise 7.3 percent with a total of 9.6 million 20-foot containers coming through U.S. docks.

Cargo import volume for 2016 totaled 18.8 million containers, up 3.1 percent from 2015.

February’s volumes, the last month with complete numbers, were off by 7 percent from last year, but that was due to a lull in retailers stocking their inventory for summer, the report said.

The “Global Port Tracker” report predicts that container traffic in March will see a 21.5 percent jump to 1.61 million containers from the same period last year when the Chinese Lunar New Year came a week later than this year.

April volumes are forecast to rise 10.3 percent to 1.59 million containers. May should be up 10.3 percent from last year to 1.68 million containers, and June will see a 5.3 percent rise. That will be followed by a 5.1 percent increase in July’s volumes and a 1.6 percent nudge in August traffic.

The National Retail Federation is forecasting that retail sales this year—excluding automobiles, gasoline and restaurants—will expand 3.7 percent to 4.2 percent over last year, driven by job and income growth coupled with low debt.