Year	Percent
1960	74.87031
1961	82.02545
1962	95.76163
1963	95.66213
1964	97.63571
1965	91.63255
1966	91.42834
1967	83.67239
1968	92.71016
1969	98.20847
1970	97.99631
1971	92.76505
1972	104.10278
1973	97.73184
1974	105.35024
1975	130.99047
1976	118.48575
1977	129.33064
1978	136.66801
1979	143.98617
1980	134.01797
1981	145.67133
1982	122.17573
1983	100.5291
1984	117.11712
1985	116.18456
1986	102.26026
1987	88.95317
1988	94.31566
1989	93.90059
1990	83.2829
1991	84.99716
1992	80.07887
1993	74.30452
1994	70.58455
1995	67.56534
1996	65.95115
1997	70.60826
1998	67.78013
1999	75.88037
2000	89.17493
2001	78.6823
2002	74.41945
2003	76.40184
2004	69.262
2005	81.85541
2006	88.68262
2007	85.28852
2008	95.44362
2009	78.50833
2010	84.73635
2011	96.49796
2012	94.57979
2013	95.29002
2014	91.04017
2015	85.97711
2016	76.67365
2017	71.36017