fleet includes 6,225 ships of over 10,000 DWT, and represent 40% of all ships in terms of tonnage and 39.4% in terms of vessels. Including smaller ships, bulk carriers have a total combined capacity of almost 346 million DWT. Combined carriers are a very small portion of the fleet, representing less than 3% of this capacity. The lake freighters of the Great Lakes, with 98 ships of 3.2 million total DWT, despite forming a small fraction of the total fleet by tonnage and only operating 10 months a year, carried a tenth of the world's bulk cargo because of the short trip distance and fast turnarounds. As of 2005, the average bulk carrier was just over 13 years old. About 41% of all bulk carriers were less than ten years old, 33% were over twenty years old, and the remaining 26% were between ten and twenty years of age. All of the 98 bulk carriers registered in the Great Lakes trade are over 20 years old and the oldest still sailing in 2009, the St. Mary's Challenger, was 106 years old. Flag states As of 2005, the United States Maritime Administration counted 6,225 bulk carriers of or greater worldwide. More bulk carriers are registered in Panama, with 1,703 ships, more than any four other flag states combined. In terms of the number of bulk carriers registered, the top five flag states also include Hong Kong with 492 ships, Malta (435), Cyprus (373), and China (371). Panama also dominates bulk carrier registration in terms of deadweight tonnage. Positions two through five are held by Hong Kong, Greece, Malta, and Cyprus. Largest fleets Greece, Japan, and China are the top three owners of bulk carriers, with 1,326, 1,041, and 979 vessels respectively. These three nations account for over 53% of the world's fleet. Several companies have large private bulk carrier fleets. The multinational company Gearbulk Holding Ltd. has over 70 bulk carriers. The Fednav Group in Canada operates a fleet of over 80 bulk carriers, including two designed to work in Arctic ice. Croatia's Atlantska Plovidba d.d. has a fleet of 14 bulk carriers. The H. Vogemann Group in Hamburg, Germany operates a fleet of 19 bulk carriers. Portline in Portugal, owns 10 bulk carriers. Dampskibsselskabet Torm in Denmark and Elcano in Spain also own notable bulk carrier fleets. Other companies specialize in mini-bulk carrier operations: England's Stephenson Clarke Shipping Limited owns