There shall be excluded from the gross receipts by which the tax is measured:
(a) The amount of any sales or use tax imposed by the State of California upon a retailer or consumer;
(b) Eighty percent of the gross receipts from the sale of tangible personal property to operators of waterborne vessels to be used or consumed principally outside the County in which the sale is made and directly and exclusively in the carriage of persons or property in such vessels for commercial purposes;
(c) Eighty percent of the gross receipts from the sale of tangible personal property to operators of aircraft to be used or consumed principally outside the county in which the sale is made and directly and exclusively in the use of such aircraft as common carriers of persons or property under the authority of the laws of this State, the United States, or any foreign government.
(Ord. 363-58, App. 6/23/58; amended by Ord. 352-84, App. 8/8/84)