Year	Percent
1960	0.07739
1961	5.72846
1962	14.27698
1963	14.44149
1964	68.79975
1965	70.26442
1966	56.10779
1967	44.9308
1968	32.53976
1969	31.37291
1970	38.11209
1971	84.08672
1972	36.54583
1973	40.15038
1974	32.70379
1975	41.41597
1976	43.63705
1977	36.66794
1978	40.43978
1979	37.49662
1980	41.42488
1981	40.13721
1982	22.77384
1983	44.7634
1984	55.85155
1985	100.45307
1986	74.85879
1987	66.19726
1988	62.36557
1989	150.88862
1990	96.84369
1991	92.3722
1992	116.50751
1993	78.78404
1994	90.11824
1995	60.37066
1996	69.56746
1997	52.57299
1998	46.04399
1999	31.69412
2000	43.43788
2001	43.08492
2002	35.60722
2003	37.22985
2004	41.58808
2005	43.97749
2006	44.20707
2007	35.52682
2008	47.34414
2009	46.80197
2010	46.31303
2011	38.20792
2012	29.84039
2013	27.96154
2014	23.42668
2015	18.49367
2016	20.8966
2017	22.34365
2018	15.27043
2019	16.08216
2020	26.09177
2021	16.53129