For temperature below E85 flex vehicles require an engine block heater. The use of this device is also recommended for gasoline vehicles when temperatures drop below . Another option when extreme cold weather is expected is to add more pure gasoline in the tank, thus reducing the ethanol content below the E75 winter blend, or simply not to use E85 during extreme low temperature spells. Sweden has achieved the largest E85 flexible-fuel vehicle fleet in Europe, with a sharp growth from 717 vehicles in 2001 to 243,136 through December 2014. As of 2008 a total of 70% of all flexifuel vehicles operating in the EU were registered in Sweden. The recent and accelerated growth of the Swedish fleet of E85 flexifuel vehicles is the result of the National Climate Policy in Global Cooperation Bill passed in 2005, which not only ratified the Kyoto Protocol but also sought to meet the 2003 EU Biofuels Directive regarding targets for use of biofuels, and also let to the 2006 government's commitment to eliminate oil imports by 2020. In order to achieve these goals several government incentives were implemented. Ethanol, as the other biofuels, was exempted of both, the CO2 and energy taxes until 2009, resulting in a 30% price reduction at the pump of E85 fuel over gasoline. Furthermore, other demand side incentives for flexifuel vehicle owners include a bonus to buyers of FFVs, exemption from the Stockholm congestion tax, up to 20% discount on auto insurance, free parking spaces in most of the largest cities, owner annual registration taxes, and a 20% tax reduction for flexifuel company cars. Also, a part of the program, the Swedish Government ruled that 25% of their vehicle purchases (excluding police, fire and ambulance vehicles) must be alternative fuel vehicles. By the first months of 2008, this package of incentives resulted in sales of flexible-fuel cars representing 25% of new car sales. On the supply side, since 2005 the gasoline fuelling stations selling more than 3 million liters of fuel a year are required to sell at least one type of biofuel, resulting in more than 1,200 gas stations selling E85 by August 2008. Despite all the sharp growth of E85 flexifuel cars, by 2007 they represented just two percent of the four million Swedish vehicles. In addition, this law also mandated all new filling stations to offer alternative fuels, and stations with an annual volume of