Year	%
1992	42.09
1993	39.08
1994	35.51
1996	23.7
1997	17.51
1998	18.28
1999	17.12
2000	16.99
2001	15.88
2002	13.11
2003	11.36
2004	10.52
2005	9.81
2006	9.87
2007	10.01
2008	9.7
2009	9.62
2010	9.74
2011	9.8
2014	9.67
2015	11.04
2016	10.93
2017	11.01
2018	9.86
2019	7.45
2020	7.56
2021	7.49