Despite its relative small size, natural gas use accounted for about 52% of all alternative fuels consumed by alternative transportation fuel vehicles in the U.S. in 2009.In the US a motor vehicle is specifically defined as a contrivance used for commercial purposes. As defined in US Code
18 U.S.C. § 31 : US Code - Section 31: Definitions (6) Motor vehicle. - The term "motor vehicle" means every description of carriage or other contrivance propelled or drawn by mechanical power and used for commercial purposes on the highways in the transportation of passengers, passengers and property, or property or cargo. Europe
The 27 European Union (EU-27) member countries had a fleet of over 256 million in 2008, and passenger cars accounted for 87% of the unions fleet. The five largest markets, Germany (17.7%), Italy (15.4%), France (13.3%), the UK (12.5%), and Spain (9.5%), accounted for 68% of the regions total registered fleet in 2008. The EU-27 member countries had in 2009 an estimated ownership rate of 473 passenger cars per 1000 people.According to Wards, Italy had the second highest (after the U.S.) vehicle ownership per capita in 2010, with 690 vehicles per 1000 people. Germany had a rate of motorization of 534 vehicles per 1000 people and the UK of 525 vehicles per 1000 people, both in 2008. France had a rate of 575 vehicles per 1000 people and Spain 608 vehicles per 1000 people in 2007.
Brazil
The Brazilian vehicle fleet reached 64.8 million vehicles in 2010, up from 29.5 million units in 2000, representing a 119% growth in ten years, and reaching a motorization rate of 340 vehicles per 1000 people. In 2010 Brazil experienced the second largest fleet increase in the world after China, with 2.5 million vehicle registrations.As of 2018, Brazil has the largest alternative fuel vehicle fleet in the world with about 40 million alternative fuel motor vehicles in the road. The clean vehicle stock includes 30.5 million flexible-fuel cars and light utility vehicles and over 6 million flex-fuel motorcycles by March 2018; between 2.4 and 3.0 million neat ethanol vehicles still in use, out of 5.7 million ethanol only light-vehicles produced since 1979; and, as of December 2012, a total of 1.69 million natural gas vehicles.In addition, all the Brazilian gasoline-powered fleet is designed to operate with high ethanol blends, up to 25% ethanol fuel (E25). The market share of flex fuel vehicles reached 88.6% of all light-duty vehicles registered in 2017. India
Indias vehicle fleet had the second-largest growth rate after China in 2010, with 8.9%. The fleet went from 19.1 million in 2009 to 20.8 million units in 2010. Indias vehicle fleet has increased to 210 million in March 2015. India has a fleet of 1.1 million natural gas vehicles 
as of December 2011 .