Year $ 2011 PPP (USD) 1997 0.0139734 1998 0.0101763 1999 0.0136914 2000 0.0190606 2001 0.019142 2002 0.01717 2003 0.017154 2004 0.0146467 2005 0.0180257 2006 0.0179195 2007 0.0233976 2008 0.0238696 2009 0.0278651 2010 0.0298516 2011 0.0280679 2012 0.0278214 2013 0.0218177