Year	%
1988	28.58
1989	28.59
1990	19.82
1992	19.74
1993	22.92
1994	22.06
1995	20.31
1996	14.34
1997	12.74
1998	10.68
1999	9.73
2000	7.6
2001	7.3
2002	5.72
2003	4.74
2004	6.27
2005	6.27
2006	6.26
2007	6.26
2008	6.28
2009	6.29
2010	6.28
2011	6.2
2012	6.2
2013	6.32
2015	6.31
2016	6.3
2017	6.31
2018	6.2
2019	6.17
2020	6.17
2021	6.16