Year	%
1988	29.79
1989	29.79
1990	20.86
1992	20.67
1993	24.8
1994	23.09
1995	22.13
1996	16.46
1997	16.21
1998	11.73
1999	10.91
2000	8.18
2001	8.19
2002	6.65
2003	5.74
2004	6.16
2005	6.18
2006	6.11
2007	5.96
2008	6.24
2009	6.28
2010	6.26
2011	4.94
2012	4.85
2013	4.8
2015	4.67
2016	5.79
2017	4.58
2018	5.92
2019	4.54
2020	4.47
2021	4.95