Year	Percent
1983	2.57
1984	2.65
1985	2.6
1986	2.74
1987	2.59
1988	2.55
1989	2.42
1990	2.19
1991	2.33
1992	3.09
1993	2.82
1994	2.82
1995	2.82
1996	2.72
1997	2.82
1998	3.02
1999	2.77
2000	2.83
2001	3.09
2002	2.97
2003	2.93
2004	1.75
2005	1.23
2006	1.27
2007	1.3
2008	1.2
2009	1.14
2010	1.18
2011	1.13
2012	1.07
2013	1
2014	0.98
2015	1.01
2016	1.07
2017	1