Year	Percent
1987	4.97
1988	5.03
1989	4.76
1990	3.82
1991	3.44
1992	3.6
1993	3.76
1994	3.73
1995	3.24
1996	2.27
1997	2.24
1998	1.9
1999	1.8
2000	1.43
2001	1.07
2002	1.01
2003	0.95
2004	0.89
2005	0.87
2009	0.71
2010	0.67
2011	0.73
2012	0.5
2013	0.46
2014	0.4
2015	0.31
2016	0.43