A/RES/50/20 Page 3 8. Decides, as an ad hoc arrangement, to apportion the amount referred to in paragraph 7 above among Member States 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 and 47/218 A of 23 December 1992 and its decision 48/472 A of 23 December 1993, and taking into account the scale of assessments for the years 1995 and 1996, 3/ subject to the decision of the Security Council to extend the mandate of the United Nations Disengagement Observer Force beyond 30 November 1995 and the mandate periods to be decided upon by the Council; 9. Decides also 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 8 above, their respective share in the Tax Equalization Fund of the estimated staff assessment income of 532,000 dollars for the period from 1 December 1995 to 30 June 1996, inclusive; 10. Decides further that there shall be set off against the apportionment among Member States, as provided for in paragraph 8 above, their respective share in the estimated other income of 9,000 dollars for the period from 1 December 1995 to 30 June 1996, inclusive; 11. Decides that there shall be set off against the apportionment among Member States, as provided for in paragraph 8 above, their respective share in the unencumbered balance of 805,000 dollars gross (891,000 dollars net) for the period from 1 December 1993 to 30 November 1994, inclusive, pursuant to General Assembly decision 49/413 B; 12. Invites voluntary contributions to the United Nations Disengagement Observer Force 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 established by the General Assembly in its resolutions 43/230 of 21 December 1988, 44/192 A of 21 December 1989 and 45/258 of 3 May 1991; 13. Decides also to keep the sub-item entitled "United Nations Disengagement Observer Force", under the agenda item entitled "Financing of the United Nations peace-keeping forces in the Middle East", under review during its fiftieth session. 76th plenary meeting 1 December 1995 3/ See resolution 49/19 B.