Year	World Bank estimate
1992	29.7
1993	28.9
1995	39.3
1996	35.2
2002	29
2003	28.7
2004	28.9
2005	29
2006	29.8
2007	27
2008	26.6
2009	25.3
2010	24.8
2011	24.6
2012	24.7
2013	24.6
2014	24
2015	25.5
2016	25