Year	Percent
1992	13.65
1993	14.39
1994	14.83
1995	13.7
1996	12.68
1997	10.96
1998	9.94
1999	12.29
2000	16.31
2001	18.37
2002	19.89
2003	19.37
2004	19.07
2005	17.75
2006	13.84
2007	9.6
2008	7.12
2009	8.17
2010	9.64
2011	9.63
2012	10.09
2013	10.33
2014	8.99
2015	7.5
2016	6.16
2017	4.89
2018	3.85
2019	3.28
2020	3.16