Year	Percent
1989	1.46
1990	1.4
1991	1.31
1992	1.28
1993	1.31
1994	1.27
1995	1.51
1996	1.51
1997	1.02
1998	0.57
1999	0.81
2000	0.67
2001	0.64
2002	0.52
2003	0.41
2004	0.42
2005	0.53
2006	0.55
2007	0.56
2008	0.51
2009	0.54
2010	0.56
2011	0.47
2012	0.5
2013	0.46
2014	0.49
2015	0.47
2016	0.53
2017	0.42