2005年上一次购买力平价计算时，所使用的方法是选取15个最贫困国家的国家贫困线，计算它们的平均值作为全球贫困线。
In 2005, when the previous round of purchasing power parities was estimated, the method used was to take the national poverty lines of the 15 poorest countries, compute their average, and treat that as the global line.