Year	Percent
1989	1.17
1990	1.09
1991	0.96
1992	0.93
1993	0.99
1994	0.8
1995	1.35
1996	1.39
1997	0.84
1998	0.5
1999	0.76
2000	0.61
2001	0.59
2002	0.49
2003	0.4
2004	0.32
2005	0.44
2006	0.49
2007	0.45
2008	0.42
2009	0.41
2010	0.49
2011	0.35
2012	0.4
2013	0.33
2014	0.38
2015	0.37
2016	0.47
2017	0.35