Year	Percent
1960	0.08741
1961	25.45285
1962	25.16606
1963	26.87777
1964	24.97955
1965	25.20862
1966	36.47508
1967	43.1382
1968	57.41324
1969	58.98245
1970	66.23036
1971	78.14125
1972	76.80919
1973	77.0916
1974	82.12192
1975	79.7016
1976	97.09101
1977	88.09805
1978	85.31944
1979	83.96863
1980	81.43476
1981	71.01224
1982	76.39674
1983	73.61318
1984	75.3404
1985	75.19797
1986	59.65823
1987	54.15878
1988	67.29409
1989	65.28167
1990	65.65654
1991	59.03415
1992	55.34198
1993	60.98117
1994	52.83161
1995	56.07791
1996	103.16687
1997	80.4677
1998	83.17317
1999	92.93956
2000	87.17151
2001	111.20717
2002	92.96302
2003	97.22195
2004	93.81703
2005	110.39238
2006	111.9003
2007	117.97255
2008	156.82999
2009	140.35804
2010	142.74223
2011	143.76568
2012	147.9104
2013	125.02655
2014	125.19988
2015	102.18433
2016	105.22851
2017	110.24545