SECTION 1. The tax paid by the grantee of a franchise, his lessees, successors or assigns, on the gross earnings or receipts of the business covered by the law granting the franchise; or any amendment thereof, shall be apportioned between the Insular Government, the province or provinces, and the municipality or municipalities within which such business is carried on, in the following proportion:
Where the franchise is for the operation of a steam railroad or marine railway, five-tenths to the Insular Government, two-tenths to the province or provinces concerned, and three-tenths to the municipality or municipalities concerned;
Where the franchise is for the operation of an interurban electric or tramway line, one-fifth to the Insular Government, one-fifth to the province or provinces concerned and three-fifths to the municipality or municipalities concerned;
Where the franchise is for a municipal public service entirely within the limits of the municipality, one-fifth to the Insular Government, one-fifth to the province and three-fifths to the municipality: Provided, That if, under the franchise, the grantee, his lessees, successors or assigns, is entitled to, and does in fact, transact business in any other municipality, then the said gross earnings tax shall.be apportioned between the municipalities or provinces concerned in proportion to the gross receipts from business transacted within their respective limits.
For the purposes of this apportionment the city of Manila shall be considered both as a province and a municipality. Except as above provided, the part of this tax accruing to the provinces shall be apportioned in proportion to the population of their respective municipalities in which such business is carried on, and the part corresponding to the municipalities shall be apportioned in proportion to their respective populations, all as shown by the official census last taken before the making of such apportionment: Provided, however, That if the grantee has issued bonds the payment of interest on which is guaranteed by the Insular Government according to the provisions of the law granting the franchise, or any amendment thereof, the tax shall accrue in its entirety to the Insular Government until the guaranty of the Government shall have ceased.