The appropriations entered in the State budget as part of the general decentralisation grant and intended to compensate for the expenditure of municipal hygiene offices which, on 1 January 1984, the date on which section 4 of title 2 of law no. 83-663 of 22 July 1983 supplementing law no. 83-8 of 7 January 1983 relating to the distribution of powers between municipalities, departments, regions and the State, actually exercised powers in the field of vaccination or disinfection as well as in the field of administrative and technical control of hygiene rules, are distributed among the municipalities concerned in proportion to the average credits allocated for this purpose in 1981, 1982 and 1983 to each of them.