Year	Percent
1975	0.87084
1976	0.82177
1977	0.93663
1978	0.92817
1979	0.83912
1980	0.67139
1981	0.63175
1982	0.63348
1983	0.6852
1984	0.72776
1985	0.74384
1986	0.7695
1987	0.63521
1994	1.23237
1995	0.97098
1996	0.8614
1997	0.93259
1998	1.06122
1999	1.16691
2000	1.16461
2001	1.32016
2002	0.96335
2003	0.93176
2004	1.09119
2005	0.97353
2008	0.99254
2009	0.98201
2010	1.16969
2011	1.3098
2012	2.14436
2013	1.38322
2014	1.76586
2016	2.24316
2017	2.67476