The amount of total cargo traveling through the Port of Milwaukee decreased 30 percent in 2012.
The amount went from nearly 2.9 million metric tons in 2011 to about 2 million metric tons in 2011.
Port officials say the biggest factor driving the decline was last year's mild winter, which led to smaller volumes of both salt and coal arriving by ship.
Typical cargo coming through Milwaukee includes steel that is used in local manufacturing and large finished goods that are shipped around the world.
The amount of cargo traveling to and from foreign ports increased nearly 35 percent in 2012. The port also saw increases in steel, grain, and cement in 2012 over 2011.