Iron ore needs to fall as much as 20 percent to spur Chinese importers to replenish port inventories and increase demand for ships to deliver the additional cargo, according to Arctic Securities ASA. Stocks at ports in China, the biggest consumer of the raw material used to make steel, fell 3.8 percent to 66.3 million metric tons in the week ended March 8, the lowest since March 2009, according to Beijing Antaike Information Development Co, a State-backed research company.