Year	Percent
1960	0.21226
1961	0.25862
1962	22.51784
1963	31.46649
1964	12.51197
1965	91.09447
1966	33.53205
1967	36.44057
1968	26.06992
1969	15.4191
1970	12.35336
1971	8.19892
1972	6.26532
1973	3.77896
1974	2.40679
1975	2.29775
1976	2.75367
1977	1.50378
1978	1.7882
1979	3.29932
1980	4.25689
1981	3.78692
1982	6.19176
1983	3.36512
1984	7.10506
1985	19.06338
1986	5.86204
1987	8.59758
1988	8.77894
1989	7.6333
1990	5.5041
1991	4.73469
1992	3.65738
1993	0.15902
1994	1.90667
1995	3.23199
1996	2.26093
1997	1.45836
1998	1.7655
1999	3.09055
2000	0.90419
2001	1.71132
2002	2.20112
2003	2.06323
2004	2.26104
2005	1.07185
2006	0.7353
2007	1.16031
2008	1.22742
2009	1.22732
2010	1.36406
2011	1.67063
2012	1.76436
2013	1.0314
2014	1.07044
2015	1.67816
2016	1.01604
2017	0.65478
2018	0.40463
2019	0.56604
2020	1.87007
2021	1.51476