Year	World Bank estimate
1989	54.3
1992	53.7
1994	54.3
1996	54.8
1998	53.4
2000	52.6
2002	50.1
2004	50
2005	50.1
2006	48.9
2008	49.9
2010	47.2
2012	48.7
2014	48.7
2016	48.3