This percentage is very low in comparison to the requirements of the water and sanitation sector, where such stocks should be not less than 15 per cent if preventive and unanticipated maintenance are to be carried out in the optimum manner.
与供水和卫生部门的需要相比，这个比例是极低的，因为缓冲存货不应当少于15％，这样预防性的和临时性的维修才能够高质量地进行。