Year	Percent
1960	0.71039
1961	4.4538
1962	13.40314
1963	11.93756
1964	38.93672
1965	46.87291
1966	48.74233
1967	54.25479
1968	59.90105
1969	52.21254
1970	46.70944
1971	40.12356
1972	34.33139
1973	40.87262
1974	50.24175
1975	40.75085
1976	35.80212
1977	49.28707
1978	58.03681
1979	68.40743
1980	72.05939
1981	85.60907
1982	66.83012
1983	66.06995
1984	88.47487
1985	52.89491
1986	65.58107
1987	58.87011
1988	58.34488
1989	49.69261
1990	55.66852
1991	63.00488
1992	66.88754
1993	75.32638
1994	84.11706
1995	86.14847
1996	64.97755
1997	55.05324
1998	59.00841
1999	68.0157
2000	41.56645
2001	90.46094
2002	90.35496
2003	73.79566
2004	76.52258
2005	64.67594
2006	85.29779
2007	67.73498
2008	51.05365
2009	57.36298
2010	46.9883
2011	36.74269
2012	37.21163
2013	32.78546
2014	41.82686
2015	43.4795
2016	38.5751
2017	28.64458
2018	34.3786
2019	34.97097
2020	58.2808
2021	53.2446