main UN organisational budget; in the 2013–2014 fiscal year, peacekeeping expenditures totalled $7.54 billion. UN peace operations are funded by assessments, using a formula derived from the regular funding scale, but including a weighted surcharge for the five permanent Security Council members. This surcharge serves to offset discounted peacekeeping assessment rates for less developed countries. In 2020, the top 10 providers of assessed financial contributions to United Nations peacekeeping operations were the US (27.89%), China (15.21%), Japan (8.56%), Germany (6.09%), the United Kingdom (5.79%), France (5.61%), Italy (3.30%), Russian Federation (3.04%), Canada (2.73%) and South Korea (2.26%). Criticism and evaluations In examining the first sixty years of the Security Council's existence, British historian Paul Kennedy concludes that "glaring failures had not only accompanied the UN's many achievements, they overshadowed them", identifying the lack of will to prevent ethnic massacres in Bosnia and Rwanda as particular failures. Kennedy attributes the failures to the UN's lack of reliable military resources, writing that "above all, one can conclude that the practice of announcing (through a Security Council resolution) a new peacekeeping mission without ensuring that sufficient armed forces will be available has usually proven to be a recipe for humiliation and disaster". Several studies have examined the Security Council's responsiveness to armed conflict. Findings suggests that the Council is more likely to meet and deliberate on conflicts that are more intense and lead to more humanitarian suffering, but that its responsiveness is also shaped by the political interests of member states and in particular of the permanent members. A 2005 RAND Corporation study found the UN to be successful in two out of three peacekeeping efforts. It compared UN nation-building efforts to those of the United States, and found that 88% of UN cases lead to lasting peace. Also in 2005, the Human Security Report documented a decline in the number of wars, genocides and human rights abuses since the end of the Cold War, and presented evidence, albeit circumstantial, that international activism—mostly spearheaded by the UN—has been the main cause of the decline in armed conflict since the end of the Cold War. Scholar Sudhir Chella Rajan argued in 2006 that the five permanent members of the United Nations Security Council, who are all nuclear powers, have created an exclusive nuclear club that predominantly addresses the strategic interests and political motives of the permanent members—for example, protecting the oil-rich Kuwaitis in 1991