Hybrid cars have gained popularity because of their fuel economy and the uncertainty regarding the price of gasoline. All automakers, including the Ford Motor Co., have planned to significantly expand their hybrid vehicle lineup (CNN.com, November 9, 2005). The following table contains quarterly sales of Ford and Mercury hybrid cars. SOURCE: Internal Revenue Service, United States Department of Treasury . Hybrid cars have gained popularity because of their fuel economy and the uncertainty regarding the price of gasoline. All automakers, including the Ford Motor Co., have planned to significantly expand their hybrid vehicle lineup (CNN.com, November 9, 2005). The following table contains quarterly sales of Ford and Mercury hybrid cars. SOURCE: Internal Revenue Service, United States Department of Treasury