Year	Percent
1986	4.19
1987	4.21
1988	5.77
1989	7.31
1990	7.98
1991	10.61
1992	10.67
1993	9.8
1994	8.35
1995	6.46
1996	6.29
1997	6.86
1998	7.72
1999	7.02
2000	6.13
2001	5.43
2002	5.28
2003	4.75
2004	4.01
2005	3.81
2006	3.86
2007	3.66
2008	4.17
2009	6.12
2010	6.56
2011	6.49
2012	6.93
2013	5.84
2014	5.43
2015	5.41
2016	5.15
2017	4.74
2018	4.33
2019	4.11
2020	4.59