Because of the energy bill …
Effective January 2006, the energy bill replaced the tax deduction for buying hybrid cars with a much more generous tax credit, giving consumers a greater incentive to buy fuel-efficient cars. The tax credit amount ranges from $250 to $3,400, depending on the fuel economy and the weight of the automobile. Total hybrid sales in February 2006 were up nearly 44% from the same period the year before, based in part on tax credits for their purchase.