Year	%
1992	43.88
1993	40.77
1994	36.59
1996	22.98
1997	17.27
1998	18.29
1999	16.84
2000	16.47
2001	15.35
2002	12.98
2003	11.04
2004	10.18
2005	9.55
2006	9.52
2007	9.66
2008	9.33
2009	9.22
2010	9.37
2011	9.46
2014	9.44
2015	11.28
2016	11.01
2017	11.1
2018	9.54
2019	6.83
2020	6.97
2021	6.88