reducing the space for other cargo. This problem has been solved by installing the tanks under the vehicle's body or on the roof (typical for buses), leaving cargo areas free. As with alternative fuels, other barriers to the widespread use of NGVs are natural gas distribution to and at fueling stations and the lower number of CNG and LNG stations than liquid fuels. Other challenges include: relatively expensive and environmentally insensitive but convenience-seeking private individuals; good profits and taxes extractable from small-batch sales of value-added, branded petrol and diesel fuels via established trade channels and oil refiners; resistance and safety concerns to increasing gas inventories in urban areas; dual-use of utility distribution networks originally built for home gas supply and allocation of network expansion costs; reluctance, effort and costs associated with switching; prestige and nostalgia associated with petroleum vehicles; fear of redundancy and disruption. A particular challenge may be that refiners are currently set up to produce a certain fuel mix from crude oil. Aviation fuel is likely to remain the fuel of choice for aircraft due to its weight sensitivity for the foreseeable future. Deployment The Asia-Pacific region leads the world with 6.8 million vehicles, followed by Latin America with 4.2 million. In Latin America, almost 90% of NGVs have bi-fuel engines, allowing these vehicles to run on either gasoline or CNG. In Pakistan, almost every vehicle converted to (or manufactured for) alternative fuel use typically retains the capability of running on gasoline. As of 2016, the U.S. had a fleet of 160,000 NG vehicles, including 3,176 LNG vehicles. Other countries where natural gas-powered buses are popular include India, Australia, Argentina, Germany, and Greece. In OECD countries, there are around 500,000 CNG vehicles. Pakistan's market share of NGVs was 61.1% in 2010, follow by Armenia with more than 77% (2014), and Bolivia with 20%. The number of NGV refueling stations has also increased to 18,202 worldwide as of 2010, up 10.2% from the previous year. Vehicles An increasing number of vehicles worldwide are being manufactured to run on CNG by major carmakers. Until recently, the Honda Civic GX was the only NGV commercially available in the US market. More recently, Ford, General Motors and Ram Trucks have bi-fuel offerings in their vehicle lineup. In 2006, the Brazilian subsidiary of FIAT introduced the Fiat Siena Tetra fuel, a four-fuel car that can run on natural gas (CNG). CNG-powered vehicles are