Following negative numbers in four of the last five months, import volume at the nation's major retail container ports is expected to grow 1.7 percent in August over the same month last year and should continue to see gains through the holiday season and the remainder of 2013, according to the monthly Global Port Tracker report released by the National Retail Federation and Hackett Associates. The year is expected to end with a 2.4-percent increase over 2012.