Year	Percent
1970	1.62961
1973	1.86891
1974	1.61082
1975	1.72207
1976	2.04609
1977	2.01147
2004	2.43126
2005	1.99207
2006	1.89623
2007	2.56627
2008	2.33555
2009	2.08741
2010	1.94584
2011	1.82135
2012	1.17542
2013	1.07695
2014	1.29801
2015	0.99345
2016	0.95549
2017	0.90686