Year	Percent
1960	0.98462
1961	1.12765
1962	2.35686
1963	6.20733
1964	5.95693
1965	12.52527
1966	22.64354
1967	25.1231
1968	33.56825
1969	30.80313
1970	18.83812
1971	16.58504
1972	38.9424
1973	15.01392
1974	9.61763
1975	34.74923
1983	71.24432
1984	70.23819
1985	45.08125
1986	66.83322
1987	77.24497
1988	98.033
1989	103.14411
1990	65.80123
1991	83.79725
1992	74.78983
1993	47.3151
1994	41.97634
1995	50.21167
1996	44.31029
1997	28.90718
1998	40.70881
1999	37.64026
2000	50.22937
2001	45.61352
2002	56.75037
2003	56.2651
2004	56.30266
2005	36.98918
2006	26.34808
2007	30.44634
2008	27.74265
2009	37.02288
2010	40.23798
2011	35.798
2012	25.69362
2013	8.53426
2014	7.54694
2015	12.93244
2016	9.22317
2017	10.69108
2018	7.30746
2019	7.14885
2020	17.26847
2021	9.05957