Year	Percent
1960	3.70353
1961	3.51177
1962	3.58993
1963	3.25027
1964	3.33187
1965	3.07012
1966	3.27136
1967	3.04494
1968	3.04967
1969	2.81227
1970	2.56493
1971	2.58445
1972	2.21264
1973	2.28654
1974	2.01069
1975	2.15534
1976	2.04354
1977	1.99166
1978	1.66545
1979	1.54911
1980	1.50949
1981	1.46317
1982	1.34339
1983	1.17846
1984	1.06996
1985	0.92113
1986	0.717
1987	0.55061
1988	0.41698
1989	0.3559
1990	0.32344
1991	0.25005
1992	0.19736
1993	0.17279
1994	0.17316
1995	0.14486
1996	0.15003
1997	0.13292
1998	0.11138
1999	0.11125
2000	0.09213
2001	0.08236
2002	0.07103
2003	0.06113
2004	0.05565
2005	0.05505
2006	0.04887
2007	0.04287
2008	0.04143
2009	0.04069
2010	0.03615
2011	0.03461
2012	0.03327
2013	0.03438
2014	0.03454
2015	0.03261
2016	0.03158
2017	0.03078
2018	0.03014
2019	0.03219
2020	0.03289
2021	0.03147
2022	0.02811