Year	Percent
1960	0.84286
1961	28.74445
1962	33.63368
1963	36.20793
1964	44.64271
1965	31.78654
1966	34.25379
1967	48.24353
1968	70.96856
1969	49.36425
1970	44.19843
1971	35.59306
1972	31.10741
1973	29.21319
1974	42.06341
1975	24.41762
1976	27.79098
1977	23.93504
1978	23.46131
1979	25.14761
1980	27.97986
1981	27.26911
1982	43.58598
1983	70.3926
1984	100.2223
1985	87.43949
1986	85.26995
1987	55.0424
1988	92.94928
1989	89.08072
1990	59.68258
1991	72.66962
1992	83.62424
1993	103.88081
1994	84.32487
1995	90.59634
1996	56.49982
1997	51.25309
1998	49.23404
1999	34.00912
2000	20.15758
2001	13.2579
2002	12.28447
2003	9.38531
2004	10.87334
2005	16.76494
2006	17.46919
2007	17.34269
2008	42.19913
2009	72.26729
2010	53.65181
2011	50.25301
2012	25.58231
2013	16.995
2014	14.74455
2015	13.76117
2016	13.74838
2017	32.07671
2018	25.03288
2019	31.03973
2020	37.83692
2021	21.78148