Year	2011 PPP (%)
1981	17.6
1982	17.7
1983	22.1
1984	21.4
1985	18.6
1986	9.3
1987	14.8
1988	16.6
1989	15.1
1990	17.6
1992	17.4
1993	16.6
1995	11.2
1996	12.1
1997	12
1998	10.9
1999	11.4
2001	9.9
2002	9
2003	9.6
2004	8.5
2005	7.6
2006	6.4
2007	6.1
2008	5.1
2009	4.8
2011	4.1
2012	3.4
2013	3.3
2014	2.5
2015	2.9
2016	3.7
2017	4