Year	Percent
1960	10.53722
1961	9.07927
1962	9.832
1963	8.82842
1964	7.98671
1965	7.78702
1966	7.59303
1967	7.56603
1968	7.32267
1969	6.67996
1970	6.62779
1971	6.06668
1972	6.77628
1973	6.77512
1974	5.412
1975	4.81312
1976	4.55923
1977	4.31607
1978	4.17049
1979	4.1335
1980	3.60737
1981	3.53167
1982	4.05264
1983	3.59548
1984	3.35898
1985	3.33765
1986	3.23461
1987	3.08815
1988	2.84939
1989	3.125
1990	3.13684
1991	2.61435
1992	2.59288
1993	2.29573
1994	2.40069
1995	2.44477
1996	2.40428
1997	2.34426
1998	2.36246
1999	2.23626
2000	2.09836
2001	2.10701
2002	2.01086
2003	1.85016
2004	1.82269
2005	1.6801
2006	1.51849
2007	1.61299
2008	1.51522
2009	1.32316
2010	1.60403
2011	1.65029
2012	1.6318
2013	1.45863
2014	1.55636
2015	1.60564
2016	1.43711
2017	1.54241
2018	1.64888
2019	1.52246
2020	1.57949
2021	1.61723
2022	1.91365