Year	%
1988	29.08
1989	29.11
1990	20.66
1992	20.31
1993	24.23
1994	22.54
1995	21.81
1996	15.35
1997	15.79
1998	11.68
1999	10.9
2000	8.19
2001	8.11
2002	6.97
2003	6.03
2004	7.16
2005	7.17
2006	7.15
2007	7.13
2008	7.25
2009	7.28
2010	7.27
2011	7.23
2012	7.23
2013	7.62
2015	7.59
2016	7.56
2017	7.61
2018	7.56
2019	7.55
2020	7.57
2021	7.6