Year	Percent
1991	4.64
1993	8.42
1994	8.68
1995	7.79
1996	7.19
1997	6.95
1998	10.79
1999	16.57
2000	16.99
2001	16.31
2002	15.38
2003	16.76
2004	19.85
2005	19.22
2006	17.49
2007	10.75
2008	9.87
2009	16.64
2010	18.34
2011	18.07
2012	19.51
2013	18.97
2014	15.86
2015	12.6
2016	10.51
2017	7.95
2018	6.73
2019	5.63
2020	7.95