known as merchant seamen, merchant sailors, and merchant mariners, or simply seamen, sailors, or mariners. The terms "seaman" or "sailor" may also refer to a member of a country's martial navy. According to the 2005 CIA World Factbook, the total number of merchant ships of at least 1,000 gross register tons in the world was 30,936. In 2010, it was 38,988, an increase of 26%, across many countries. , a quarter of all merchant mariners were born in the Philippines. Liners and tramps A ship may also be categorized as to how it is operated. A liner will have a regular run and operate to a schedule. The scheduled operation requires that such ships are better equipped to deal with causes of potential delay such as bad weather. They are generally higher powered than tramp ships with better seakeeping qualities, thus they are significantly more expensive to build. Liners are typically built for passenger and container operation though past common uses also included mail and general cargo. A tramp (trader) has no fixed run but will go wherever a suitable cargo takes it. Thus a ship and crew may be chartered from the ship owner to fetch a cargo of grain from Canada to Latvia, the ship may then be required to carry a cargo of coal from Britain to Melanesia. Bulk carriers and some cruise ships are examples of ships built to operate in this manner. Ships and watercraft Ships and other watercraft are used for maritime transport. Types can be distinguished by propulsion, size or cargo type. Recreational or educational craft still use wind power, while some smaller craft use internal combustion engines to drive one or more propellers, or in the case of jet boats, an inboard water jet. In shallow-draft areas, such as the Everglades, some craft, such as the hovercraft, are propelled by large pusher-prop fans. Most modern merchant ships can be placed in one of a few categories, such as: Typical in-transit times A cargo ship sailing from a European port to a US one will typically take 10–12 days depending on water currents and other factors. In order to make container ship transport more economical, ship operators sometimes reduce cruising speed, thereby increasing transit time, to reduce fuel consumption, a strategy referred to as "slow steaming". History Professional mariners A ship's complement can be divided into four categories: The deck department The engine