Year	Percent
1961	2.92875
1962	2.92875
1963	2.92875
1964	2.92875
1965	2.94283
1966	2.95691
1967	2.95691
1968	2.95691
1969	2.95691
1970	2.98507
1971	2.98507
1972	2.98507
1973	2.99916
1974	3.01324
1975	3.02732
1976	3.0414
1977	3.05548
1978	3.06956
1979	3.08364
1980	3.13996
1981	3.19628
1982	3.19628
1983	3.26669
1984	3.26669
1985	3.30893
1986	3.35117
1987	3.35117
1988	3.36525
1989	3.36525
1990	4.01295
1991	4.36497
1992	4.7733
1993	4.99859
1994	5.23796
1995	5.39285
1996	5.44917
1997	5.56181
1998	5.60406
1999	7.26556
2000	7.70206
2001	7.91326
2002	7.96959
2003	7.80062
2004	7.80062
2005	7.84286
2006	7.58378
2007	7.4993
2008	7.59786
2009	5.46184
2010	5.5238
2011	5.47029
2012	5.30414
2013	5.34216
2014	5.38581
2015	5.39003
2016	5.40411
2017	5.40411
2018	5.37525
2019	5.49704
2020	5.48859
2021	5.5134