The Farmers Insurance Group of Companies announced this week it is the first in the U.S. to offer an insurance discount to customers who own a hybrid or alternative-fuel vehicle. The discount amount will be 5 percent for auto customers in California.The discount, effective October 1, 2005, is for all customers who own a hybrid or alternative-fuel vehicle. All new business customers will receive the discount as of the new business date, and existing customers will receive the discount upon renewal.According to R. L. Polk & Co, a firm that collects and interprets automotive information, California tops the list for the number of registered hybrid vehicles in the U.S. In 2004, over 25,000 hybrid vehicles were registered in the state of California -- a 102 percent increase over 2003. The use of alternative-fuel vehicles -- vehicles that utilize biodiesel, electricity, ethanol, hydrogen, natural gas, and propane -- has also increased in California from 66,366 vehicles in 2001 to 77,761 vehicles in 2003.