Year	Percent
1967	1.10778
1968	1.01509
1969	1.3676
1970	1.4324
1971	1.44053
1972	1.55023
1973	1.30354
1974	0.67958
1975	0.78071
1976	0.66847
1977	1.0297
1979	1.87713
1980	1.60363
1981	2.2868
1982	2.44764
1983	2.55359
1984	2.25549
1985	2.85905
1986	3.99593
2000	1.80145
2001	1.79395
2002	1.78317
2003	1.66833
2004	1.61317
2005	1.24868
2006	1.28262
2010	1.87162
2011	1.46243
2012	1.6198
2013	1.60405
2014	1.14482
2015	1.1946
2016	1.42725
2017	2.05564