46. 为享受规模经济带来的好处，也为使机构间集合基金成为在国家一级加强全系统一致性的重心，根据以往经验估计，15-20%的非核心支出应导向机构间集合基金。16 2015 年，仅有 16 个方案国达到 20%的门槛，另有 6 个国家达到 15%的门槛。在大多数方案国，流经机构间集合基金的非核心支出不到 5%(见图十一)。多数方案国未达到目标份额的一个主要原因是，此类捐助的捐助方基数小。2015年，机构间集合基金收到的捐助中有 63%来自荷兰、挪威、瑞典与联合王国这四个捐助国。
46. In order to reap the benefits of economies of scale and for inter-agency pooled funds to act as gravity centres for strengthening system-wide coherence at the country level, based on past experience it is estimated that at least 15-20 per cent of non-core expenditures should be channelled to inter-agency pooled funds.17 In 2015, only 16 programme countries reached the 20 per cent threshold, and in anothe r 6 countries the 15 per cent threshold was obtained. In the majority of programme countries, less than 5 per cent of non-core expenditures were channelled through inter-agency pooled funds (see figure XI). One of the main reasons for the target share not being achieved in more programme countries is the narrow donor base for such contributions. Just four donors, namely the Netherlands, Norway, Sweden and the United Kingdom, accounted for 63 per cent of all contributions to inter-agency pooled funds in 2015.