To determine the share of the compensation entitlement of each of the competent authorities in each department, account shall be taken of and distinguished, subject to articles R. 1614-69 et R. 1614-70, the expenditure borne by the State in respect of the special public road transport services reserved for pupils and existing during the 1983-1984 school year on the one hand, and the travel of pupils on the regular lines existing during the same school year on the other.