Year	2017 PPP (%)
1997	31.8
1998	31.8
1999	32.2
2000	31.5
2001	33.1
2002	30.2
2003	28.7
2004	29.2
2005	31
2006	27.5
2007	23.9
2008	21.1
2009	19.5
2010	17
2011	15.8
2012	14.5
2013	13.9
2014	13.2
2015	12.8
2016	12.6
2017	12.6
2018	11.3
2019	10.4
2020	17.2
2021	11.4
2022	11.1