Year	%
1991	13.03
1995	11.79
1996	12.16
1997	12.48
1998	12.22
1999	15.21
2000	14.64
2001	14.51
2002	14.7
2003	14.51
2004	12.8
2005	11.87
2006	11.76
2007	10.04
2008	9.27
2009	7.09
2010	4.43
2011	4.1
2012	3.76
2013	3.69
2014	3.67
2015	3.75
2016	3.85
2017	4.06
2018	3.73