Year	%
1990	28.07
1992	21.31
1993	30.15
1994	12.32
1995	27.19
1996	26.57
1997	15.47
1998	25.03
1999	15.23
2000	18.61
2001	15.06
2002	15.52
2003	12.47
2004	9.49
2005	8.17
2006	8.84
2007	7.25
2008	9.37
2009	8.37
2010	9.94
2011	8.32
2012	6.2
2013	5.46
2014	5.03
2015	5.11
2016	5.28
2017	5.05