Year	Percent
1960	48.73201
1961	52.07156
1962	56.64273
1963	62.92731
1964	57.11291
1965	55.25517
1966	54.98971
1967	57.44181
1968	58.23721
1969	59.24589
1970	56.46004
1971	58.41163
1972	57.46704
1973	52.18672
1974	68.34608
1975	74.88
1976	66.07693
1977	63.20797
1978	63.08275
1979	59.80695
1980	81.28647
1981	68.92298
1982	52.78008
1983	45.87875
1984	44.16115
1985	48.08718
1986	46.30415
1987	79.56834
1988	63.62977
1989	66.34076
1990	62.70667
1991	105.90766
1992	127.55531
1993	117.37998
1994	104.95197
1995	101.21057
1996	102.62131
1997	99.66007
1998	95.93275
1999	96.50847
2000	96.07997
2001	94.99327
2002	92.77214
2003	89.81385
2004	95.79317
2005	84.62287
2006	50.37187
2007	51.23143
2008	52.79473
2009	48.93282
2010	51.38472
2011	55.34103
2012	59.86939
2013	51.52497
2014	43.82068
2015	41.25673
2016	45.84443
2017	43.70133