Year	Percent
1965	13.14923
1966	12.09306
1967	11.74623
1968	10.92079
1969	10.44768
1970	12.12056
1971	12.00296
1972	10.94735
1973	11.53074
1974	11.47856
1975	11.13875
1976	10.61793
1977	10.51597
1978	10.26948
1979	9.18271
1980	6.31871
1981	6.35982
1982	5.37348
1983	5.93525
1984	6.42201
1985	6.53973
1986	6.80768
1987	6.41647
1988	6.47809
1989	6.4526
1990	6.6671
1991	6.49699
1992	5.99898
1993	4.79415
1994	4.36385
1995	4.13057
1996	4.57994
1997	4.21889
1998	3.90765
1999	3.49018
2000	3.15927
2001	3.22549
2002	3.11036
2003	3.20736
2004	3.18595
2005	2.94567
2006	2.94296
2007	3.04187
2008	3.02876
2009	3.1006
2010	3.09201
2011	2.97569
2012	3.04873
2013	3.02454
2014	3.02714
2015	3.08519
2016	3.24629
2017	3.29751
2018	3.29696
2019	3.31221
2020	3.71222
2021	3.79341
2022	4.03328