Year	Percent
1960	9.53337
1961	9.28505
1962	8.78175
1963	8.77332
1964	9.04018
1965	9.21181
1966	8.24796
1967	7.81604
1968	7.85167
1969	6.91315
1970	6.47508
1971	6.51163
1972	6.69979
1973	6.31905
1974	7.08796
1975	6.2406
1976	7.0821
1977	7.17849
1978	6.23385
1979	7.41214
1980	7.73585
1981	7.87402
1982	7.86885
1983	7.18732
1984	7.75463
1985	8.19015
1986	9.31538
1987	10.40816
1988	10.07752
1989	8.99373
1990	8.08445
1991	8.815
1992	11.15505
1993	18.87776
1994	16.32198
1995	13.98638
1996	14.78348
1997	11.70173
1998	8.38727
1999	8.44662
2000	9.53925
2001	9.09487
2002	6.70477
2003	6.47972
2004	5.22488
2005	4.91937
2006	9.99167
2007	10.14762
2008	8.92968
2009	9.84208
2010	9.47219
2011	8.73236
2012	8.38506
2013	8.48595
2014	9.38476
2015	10.40843
2016	10.76804
2017	10.91776
2018	10.03247
2019	8.59608
2020	8.13603
2021	8.90016
2022	8.05874