Year	% of total
1990	55.209851355290006
1991	57.135160098522164
1992	58.31091984938139
1993	63.146819703491154
1994	61.42960812772134
1995	63.809173411822414
1996	83.48406845693613
1997	84.41993578109731
1998	83.06609307782557
1999	83.84745542105948
2000	78.93318965517241
2001	79.89044255441834
2002	93.24789858068073
2003	91.14525139664804
2004	87.36279607163489
2005	85.8125774047062
2006	72.93810896116372
2007	81.82909265482478
2008	84.72731574588903
2009	86.60902079925215
2010	92.52271829316476
2011	77.39846968805179
2012	74.50232078390923
2013	82.22487324783776
2014	80.36833477967409
2015	78.03932428690113