Year 2017 PPP (% of population) 1971 2.2 1973 1.7 1975 1.5 1977 1.2 1979 1.2 1981 0.7 1982 0.7 1984 0.7 1985 0.5 1986 1 1987 0.5 1988 0.7 1989 1.2 1990 1.2 1991 1.2 1992 0.7 1993 1.2 1994 1 1995 0.7 1996 0.2 1997 0.2 1998 0.5 1999 0.5 2000 0.2 2001 0.2 2002 0.2 2003 0.2 2004 0.2 2005 0.2 2006 0.2 2007 0.2 2008 0.2 2009 0.2 2010 0.2 2011 0.2 2012 0.2 2013 0.5 2014 0.2 2015 0.2 2016 0.2 2017 0.2 2018 0.2 2019 0.2