Year	%
1989	37.96
1990	28.7
1991	23.63
1992	21.11
1993	16.62
1994	16.17
1995	12.8
1996	17.39
1997	16.49
1998	18.04
1999	14.55
2000	14.94
2001	12.38
2002	12.04
2003	11.65
2004	10.05
2005	9.38
2006	9.04
2007	9.14
2008	9.12
2009	9.53
2010	9.99
2011	10.36
2012	10.1
2013	12.8
2014	10.26
2015	10.26
2016	9.65
2017	10.01
2018	9.25
2019	9.16
2020	9.55
2021	9.11