Year	Percent
1962	68.13708
1963	62.8012
1964	62.60233
1965	42.11177
1966	43.81903
1967	42.42533
1968	29.62336
1969	36.10438
1970	35.69952
1971	46.46704
1972	34.79026
1973	38.33943
1974	42.33956
1975	42.98098
1976	47.00131
1977	47.01168
1980	50.65762
1981	65.99917
1982	50.69454
1983	55.4188
1984	53.28754
1985	39.82732
1986	47.38746
1987	47.86503
1988	51.46969
1989	47.33286
1990	38.98999
1991	40.22429
1992	44.23418
1993	53.18824
1994	66.97096
1995	68.52603
1996	80.06645
1997	116.70359
1998	115.94747
1999	123.64251
2000	122.06327
2001	124.39318
2002	122.26333
2003	118.86415
2004	110.61821
2005	87.41738
2006	82.32565
2007	88.62129
2008	89.22435
2009	74.34221
2010	85.75843
2011	75.09531
2012	71.90499
2013	67.65332
2014	65.96329
2015	56.65848
2016	51.31465
2017	56.53478