Year 2017 PPP (%) 1984 53 1987 52.3 1990 44.3 1993 43.9 1996 37.3 1998 48.4 1999 34.6 2000 33.6 2001 31.4 2002 23.5 2003 23.1 2004 23.7 2005 21.9 2006 25.5 2007 21.8 2008 21.1 2009 19.2 2010 16.7 2011 15.2 2012 14.1 2013 12.7 2014 11.4 2015 10.1 2016 9.3 2017 7.9 2018 6.7 2019 6 2020 5.6 2021 5.3 2022 4.5 2023 3.8