You need to switch to 2005 PPP [1] in order to replicate the number from the article.<p>The numbers then does show increasing absolute numbers of poor until 1999, and then a decline getting to slightly below 1981 levels in 2011. As percentage of the worlds population it looks a bit better.<p>[1] This version uses 205 PPP: <a href="http:&#x2F;&#x2F;iresearch.worldbank.org&#x2F;PovcalNetPPP2005&#x2F;index.htm?0" rel="nofollow">http:&#x2F;&#x2F;iresearch.worldbank.org&#x2F;PovcalNetPPP2005&#x2F;index.htm?0</a>