Year	Percent
1960	0.07048
1961	6.60431
1962	13.22335
1963	9.88866
1964	28.15605
1965	39.72166
1966	33.3952
1967	28.15739
1968	31.80352
1969	29.87757
1970	29.59586
1971	38.13143
1972	35.65543
1973	45.93659
1974	65.09951
1975	37.59733
1976	41.21924
1977	47.11868
1978	68.11277
1982	243.16923
1983	384.32342
1984	250.944
1985	237.34535
1986	184.59147
1987	189.98283
1988	249.92308
1989	217.62125
1990	264.51056
1991	213.56843
1992	168.42356
1993	156.4882
1994	108.13248
1995	123.20658
1996	90.87222
1997	75.73942
1998	59.03867
1999	89.43943
2000	40.63935
2001	27.38807
2002	19.08314
2003	17.62656
2004	30.91876
2005	28.07016
2006	17.63451
2007	19.06341
2008	19.42817
2009	19.87868
2010	13.32586
2011	13.20535
2012	12.35297
2013	12.12222
2014	8.32766
2015	19.46066
2016	25.35333
2017	30.47717
2018	37.32087
2019	26.49363
2020	47.08202
2021	32.31016