Year	%
1990	28.94
1992	17.32
1993	32.41
1994	12.13
1995	32.11
1996	23.32
1997	14.43
1998	27.36
1999	17.39
2000	22.32
2001	15.15
2002	17.33
2003	13.63
2004	11.13
2005	12.66
2006	11.25
2007	10.79
2008	11.76
2009	10.99
2010	11.1
2011	10.9
2012	9.06
2013	7.94
2014	8.63
2015	8.27
2016	8.39
2017	8.28