For ease of trading, communication and financial accounting, international commodity exchanges often set a conversion factor for benchmark crude oils. For instance the conversion factor set by the New York Mercantile Exchange (NYMEX) for Western Canadian Select (WCS) crude oil traded at Hardisty, Alberta, Canada is 6.29287 U.S. barrels per cubic metre, despite the uncertainty in converting the volume for crude oil. Regulatory authorities in producing countries set standards for measurement accuracy of produced hydrocarbons, where such measurements affect taxes or royalties to the government. In the United Kingdom, for instance, the measurement accuracy required is ±0.25%.