Year	%
1988	28.36
1989	28.37
1990	19.55
1992	19.55
1993	22.54
1994	21.93
1995	19.85
1996	14.05
1997	11.87
1998	10.4
1999	9.4
2000	7.43
2001	7.06
2002	5.35
2003	4.37
2004	6
2005	5.99
2006	5.98
2007	5.99
2008	5.97
2009	5.98
2010	5.97
2011	5.88
2012	5.88
2013	5.87
2015	5.86
2016	5.86
2017	5.85
2018	5.72
2019	5.68
2020	5.68
2021	5.66