According to a 2014 report of the Hague Centre for Strategic Studies:

Great Powers... are disproportionately engaged in alliances and wars, and their diplomatic weight is often cemented by their strong role in international institutions and forums. This unequal distribution of power and prestige leads to “a set of rights and rules governing interactions among states” that sees incumbent powers competing to maintain the status quo and keep their global influence. In today’s international system, there are four great powers that fit this definition: the United States (US), Russia, China and the European Union (whereby the EU is considered to be the sum of its parts). If we distil from this description of great power attributes and capabilities a list of criteria, it is clear why these four powers dominate the international security debate. The possession of superior military and economic capabilities can be translated into measurements such as military expenditure and GDP, and nowhere are the inherent privileges of great powers more visible than in the voting mechanisms of the United Nations Security Council (UNSC), where five permanent members have an overriding veto. The top ten countries ranked on the basis of military expenditures correspond almost exactly with the top ten countries ranked on the basis of GDP with the exception of Saudi Arabia which is surpassed by Brazil. Notably, each country with a permanent seat on the UNSC also finds itself in the top ten military and economic powers. When taken as the sum of its parts, the EU scores highest in terms of economic wealth and diplomatic weight in the UNSC. This is followed closely by the US, which tops the military expenditures ranking, and then Russia and China, both of which exert strong military, economic, and diplomatic influence in the international system.[94]

Great powers by date 1815 1878 1900 1919 1939 1945 c. 2000  Austria[nb 3]