A/RES/53/18 Page 3 amount of 22,749,540 dollars gross (21,473,540 dollars net) already appropriated for the period from 1 July to 31 October 1998 under the provisions of its resolution 52/228 B; 9. Decides also, as an ad hoc arrangement, and taking into account the amount of 22,749,540 dollars gross (21,473,540 dollars net) already apportioned for the period from 1 July to 31 October 1998 under the terms of its resolution 52/228 B, to apportion the additional amount of 37,250,460 dollars gross (34,445,260 dollars net) for the period from 1 November 1998 to 30 June 1999 among Member States, at a monthly rate of 4,656,307.50 dollars gross (4,305,657.50 dollars net), in accordance with the composition of groups set out in paragraphs 3 and 4 of General Assembly resolution 43/232 of 1 March 1989, as adjusted by the Assembly in its resolutions 44/192 B of 21 December 1989, 45/269 of 27 August 1991, 46/198 A of 20 December 1991, 47/218 A of 23 December 1992, 49/249 A of 20 July 1995, 49/249 B of 14 September 1995, 50/224 of 11 April 1996, 51/218 A to C of 18 December 1996 and 52/230 of 31 March 1998 and its decisions 48/472 A of 23 December 1993 and 50/451 B of 23 December 1995, and taking into account the scale of assessments for the years 1998 and 1999, as set out in its resolution 52/215 A of 22 December 1997, subject to the decision of the Security Council to extend the mandate of the Mission beyond 17 December 1998; 10. Decides further that, in accordance with the provisions of its resolution 973 (X) of 15 December 1955, there shall be set off against the apportionment among Member States, as provided for in paragraph 9 above, their respective share in the Tax Equalization Fund of the estimated staff assessment income of 2,805,200 dollars approved for the period from 1 November 1998 to 30 June 1999; 11. Invites voluntary contributions to the Mission in cash and in the form of services and supplies acceptable to the Secretary-General, to be administered, as appropriate, in accordance with the procedure and practices established by the General Assembly; 12. Decides to keep under review during its fifty-third session the agenda item entitled "Financing of the United Nations Mission for the Referendum in Western Sahara". 50th plenary meeting 2 November 1998