Ford Motor Co. posted a 9% drop in U.S. sales of cars and light trucks for December, closing out a weak year for the company and the auto industry. The auto maker said so-called fleet sales fell 1%, while retail sales fell 13%. Improving retail sales is central to Ford's restructuring plan as the company cuts sales to rental car companies and other mass buyers to focus on higher-margin sales to dealerships. Ford, which has slipped to the No. 3 U.S. auto maker by sales, behind Japan's Toyota Motor Corp., said it sold 210,855 light vehicles in December, compared with...