Year	%
1989	31.92
1990	18.95
1991	13.21
1992	13.64
1993	12.47
1994	12.23
1995	9.52
1996	12.87
1997	12.64
1998	13.05
1999	9.13
2000	12.95
2001	12.36
2002	7.26
2003	12.26
2004	5.22
2005	5.28
2006	4.74
2007	4.86
2008	4.44
2009	4.41
2010	5.98
2011	5.65
2012	5.56
2013	6.24
2014	4.05
2015	5.36
2016	5.76
2017	3.52