The Toyota Prius (XW10) is a subcompact hybrid car that was produced by Toyota between 1997 and 2003 in Japan. The XW10 is divided into the NHW10 and its NHW11 counterpart, both of which represent the first generation of Prius series. The Toyota Prius is the first mass-produced hybrid car, and was released 2 years ahead of other manufacturers. While the NHW10 was available exclusively to Japan, it was subsequently introduced to worldwide markets in September 2000 with the NHW11. Toyota sold about 123,000 first generation Prius. Toyota's XW10 series Prius is notable as the first vehicle based on the Toyota MC platform. Planning and concept On 16 January 1992, the Toyota Motor Corporation announced the Earth Charter, a document outlining goals to develop and market low emission vehicles. In September 1993, Toyota R&D Executive Vice President Yoshirio Kimbara created G21, a committee to research cars for the 21st century. On 1 February 1994, the first official meeting of the G21 project team took place. The team determined the goal of G21 is to create a car that is resource and environmentally friendly while retaining the benefits of modern cars. The development effort was led by Takehisa Yaegashi, who was tasked with building a car that bridged the gap between electric and gasoline powered vehicles. In 1994, Toyota executive Takeshi Uchiyamada was given the task of creating a new car that would be both fuel efficient and environmentally friendly. In late 1994, the G21 team designed a concept car with a hybrid engine for the 1995 Tokyo Motor Show. The vehicle was named "Prius," the Latin word for "prior" or "before." It was shown on 27 October 1995. In late 1996, test driving began. After reviewing over 100 hybrid designs, the engineering team ultimately settled on a continuously variable transmission (CVT) design based largely on a 2000 TRW patent application, but many technical and engineering problems had to be solved within the three years that the team was given to bring the car to the Japanese market, a goal they barely achieved as the first Prius went on sale in December 1997. One major problem was the longevity of the battery, which needed to last between 7 and 10 years. The solution the engineers came up with was to keep the battery pack between 60% and 40% charged, proving to be the "sweet spot" for extending the battery life to