governed jointly by the Worldscale Associations of London and New York. Worldscale establishes a baseline price for carrying a metric ton of product between any two ports in the world. In Worldscale negotiations, operators and charterers will determine a price based on a percentage of the Worldscale rate. The baseline rate is expressed as WS 100. If a given charter party settled on 85% of the Worldscale rate, it would be expressed as WS 85. Similarly, a charter party set at 125% of the Worldscale rate would be expressed as WS 125. Recent markets The market is affected by a wide variety of variables such as the supply and demand of oil as well as the supply and demand of oil tankers. Some particular variables include winter temperatures, excess tanker tonnage, supply fluctuations in the Persian Gulf, and interruptions in refinery services. In 2006, time-charters tended towards long term. Of the time charters executed in that year, 58% were for a period of 24 or more months, 14% were for periods of 12 to 24 months, 4% were from 6 to 12 months, and 24% were for periods of less than 6 months. From 2003, the demand for new ships started to grow, resulting in 2007 in a record breaking order backlog for shipyards, exceeding their capacity with rising newbuilding prices as a result. This resulted in a glut of ships when demand dropped due to a weakened global economy and dramatically reduced demand in the United States. The charter rate for very large crude carriers, which carry two million barrels of oil, had peaked at $309,601 per day in 2007 but had dropped to $7,085 per day by 2012, far below the operating costs of these ships. As a result, several tanker operators laid up their ships. Prices rose significantly in 2015 and early 2016, but delivery of new tankers was projected to keep prices in check. Owners of large oil tanker fleets include Teekay Corporation, A P Moller Maersk, DS Torm, Frontline, MOL Tankship Management, Overseas Shipholding Group, and Euronav. Fleet characteristics In 2005, oil tankers made up 36.9% of the world's fleet in terms of deadweight tonnage. The world's total oil tankers deadweight tonnage has increased from in 1970 to in 2005. The combined deadweight tonnage of oil tankers and bulk carriers, represents 72.9% of the world's fleet. Cargo movement In 2005, 2.42 billion metric tons of