31.12. 91 Official Journal of the European Communities No L 361/1 (Acts whose publication is obligatory) COUNCIL REGULATION (ECSC, EEC, EURATOM) .No 3830/91 of 19 December 1991 amending the Staff Regulations of Officials of the European Communities and the Conditions of Employment of Other Servants of those Communities in respect of detailed rules for adjusting the remuneration THE COUNCIL OF THE EUROPEAN COMMUNITIES, Having regard to the Treaty establishing a Single Council and a Single Commission of the European Communities, and in particular Article 24 (1) thereof, Having regard to the proposal presented by the Commis- sion after consulting the Staff Regulations Committee, Having regard to the opinion of the European Parliament () Having regard to the opinion of the Court of Justice, " Having taken note of the report from the Consultation Committee set up by the Council Decision of 23 June 1981, Whereas, following its earlier decisions of 20 March 1972 and 26 June 1976, the Council, by Decision 81/1061/ Euratom, ECSC, EEC (3, established for a period of 10 years the conditions governing the adjustment of the remuneration of officials - and other servants of the Communities ; Whereas this had the effect of transforming relations between the European institutions and their officials and “other staff into a partnership, making it possible to avoid disputes on salary adjustments ; Whereas, in the light of this experience, it is necessary to confirm and lay down the detailed rules according to which the Council, acting on a proposal from the Commission, applies Articles 64 and 65 of the Staff Regu- lations, in order to maintain this partnership between the European institutions and their officials and other staff ; Whereas it is appropriate to reaffirm the principle of the parallel development, both upwards and downwards, of the purchasing power of the salaries of national central () OJ No C 129, 20. 5. 1991, p. 222 and opinion of 12 Decem- ber 1991 (not yet published in the Official Journal). (» OJ No L 386, 31. 12. 1981, p. 6. government civil servants and of officials of the European Communities ; Whereas to implement the principle of parallel develop- ment it is necessary to take account of any changes in the cost of living affecting officials of the European Commu- nities ; Whereas work is to commence, under the auspices of the Statistical Office of the European Communities, on an analysis of existing problems with a view to improving comparability of price indexes in order to speed up rationalization of the method for drawing them up; Whegeas in this context it appears desirable, for the purpodses of the annual review, that the joint index provided for in Artricle 65 of the Staff Regulations should be weighted in such a way that the Belgian index (Brus- sels capital component) counts for 25 % ; Whereas the principle of parallel development ensures that the same consideration is given to the economic and social situation as in Member States’ decisions regarding salary adjustments of national civil servants; Whereas the weightings applicable to the remuneration of officials of the European Communities in the various places of employment should be calculated with the greatest possible precision in order to ensure observance of the principle of purchasing power equivalence ; Whereas, in order to ensure observance of the principles of parallel development and purchasing power equiva- lence, it is necessary to determine the procedure by which the Council takes account of substantial changes in the cost of living for the purpose of adjusting the weightings in accordance with Article 65 (2) of the Staff Regulations ; whereas, however, if the purchasing power forecast for the reference period produces a negative trend, the adjust- ment should be reduced appropriately ;