Year	World Bank estimate
1992	51.5
1996	56.9
1999	58.7
2000	58.7
2001	57.2
2002	55.8
2003	53.4
2004	54.8
2005	53.7
2008	55.5
2009	54.4
2010	54.7
2011	53.5
2012	52.7
2013	52.8
2014	52.7
2015	51.1
2016	50.8
2017	49.7