Year	%
1989	37.96
1990	28.7
1991	23.63
1992	21.11
1993	16.62
1994	16.18
1995	14.08
1996	17.39
1997	16.49
1998	18.04
1999	15.69
2000	14.94
2001	12.38
2002	12.04
2003	11.65
2004	11.41
2005	10.8
2006	10.85
2007	11.15
2008	11.17
2009	12
2010	12.56
2011	12.91
2012	12.78
2013	12.8
2014	12.68
2015	12.37
2016	11.64
2017	12.03
2018	12.36
2019	11.98
2020	11.07
2021	10.74