LOS ANGELES, May 24 (UPI) -- The average price for a gallon of gasoline fell 1.57 cents nationwide to $1.21.80 for all grades of self- and full-service, including all taxes, according to the latest Lundberg Survey. Trilby Lundberg said Sunday it was the first drop since February, but the May 21 report found that the average price was nearly 8 cents higher than it was a year ago. According to the May 29, 1998, Lundberg Survey, the average price for a gallon of gasoline was $1.14.03. Lundberg said there could be more declines since crude oil prices are no longer rising as they were in April and earlier this month. She said there should be plenty of gasoline for the Memorial Day weekend and beyond. The survey found the following prices: Self-serve regular $1.16.05, self-serve mid-grade $1.26.21, and self-serve premium $1.34.69. Full- service regular $1.53.18, full-service mid-grade $1.61.91, and full- serve premium $1.69.30. Lundberg said the greatest declines were on the West Coast as recent supply shortages were corrected. In Los Angeles, the average price for self-serve regular fell 6.28 cents in the past two weeks to $1.41.67. She said price cuts also occurred in a number of other cities nationwide.  