Year	%
1992	39.71
1993	37.1
1994	33.32
1996	22.02
1997	16.66
1998	17.08
1999	16.34
2000	16.4
2001	15.39
2002	12.15
2003	10.69
2004	9.81
2005	9.24
2006	8.89
2007	8.93
2008	8.7
2009	8.09
2010	8.09
2011	8.13
2014	7.74
2015	7.82
2016	7.88
2017	8.46
2018	7.56
2019	5.39
2020	5.32
2021	5.31