in terms of fuel. However some manual energy is required by the crew to steer the boat and adjust the sails using lines. In addition energy will be needed for demands other than propulsion, such as cooking, heating or lighting. The fuel efficiency of a single-occupancy boat is highly dependent on the size of its engine, the speed at which it travels, and its displacement. With a single passenger, the equivalent energy efficiency will be lower than in a car, train, or plane. International transport comparisons European Public transport Rail and bus are generally required to serve 'off peak' and rural services, which by their nature have lower loads than city bus routes and inter city train lines. Moreover, due to their 'walk on' ticketing it is much harder to match daily demand and passenger numbers. As a consequence, the overall load factor on UK railways is 35% or 90 people per train: Conversely, airline services generally work on point-to-point networks between large population centres and are 'pre-book' in nature. Using yield management, overall load factors can be raised to around 70–90%. Intercity train operators have begun to use similar techniques, with loads reaching typically 71% overall for TGV services in France and a similar figure for the UK's Virgin Rail Group services. For emissions, the electricity generating source needs to be taken into account. US Passenger transport The US Transport Energy Data Book states the following figures for passenger transport in 2018. These are based on actual consumption of energy, at whatever occupancy rates there were. For modes using electricity, losses during generation and distribution are included. Values are not directly comparable due to differences in types of services, routes, etc. US Freight transport The US Transport Energy book states the following figures for freight transport in 2010: From 1960 to 2010 the efficiency of air freight has increased 75%, mostly due to more efficient jet engines. 1 gal (3.785 L, 0.833 gal) of fuel can move a ton of cargo 857 km or 462 nmi by barge, or by rail, or by lorry. Compare: Space Shuttle used to transport freight to the other side of the Earth (see above): 40 megajoules per tonne-kilometre. Net energy for lifting: 10 megajoules per tonne-kilometre. Canadian transport Natural Resources Canada's Office of Energy Efficiency publishes annual statistics regarding the efficiency of the entire Canadian fleet. For researchers, these fuel consumption estimates are