Year	Percent
1960	1.9174
1961	1.84496
1962	2.05952
1963	2.14912
1964	3.14224
1965	4.1153
1966	3.52515
1967	3.65462
1968	3.75
1969	5.19726
1970	4.95401
1971	4.60337
1972	4.19175
1973	3.16212
1974	2.56784
1975	2.25108
1976	2.66667
1977	2.6156
1978	2.04069
1979	2.59315
1980	2.3027
1981	1.78181
1982	2.44048
1983	3.26869
1984	4.08452
1985	3.3997
1986	3.22725
1987	2.55271
1988	3.55197
1990	4.81332
1991	4.9923
1992	4.38936
1993	4.92112
1994	3.89784
1995	1.66798
1996	1.26931
1997	0.9543
1998	2.37966
1999	4.00979
2000	4.48568
2001	2.46934
2002	2.64545
2003	1.84576
2004	4.61038
2005	3.27849
2006	3.58904
2007	4.08319
2008	5.04671
2009	5.25157
2015	2.35652
2016	2.49068
2017	3.18316