Year	Percent
1966	32.23559
1967	32.26371
1968	32.2449
1969	32.19979
1970	30.24323
1971	30.34934
1972	32.26351
1973	32.22656
1974	32.21477
1975	32.05282
1976	32.63915
1977	30.99636
1978	27.94364
1979	26.69293
1980	27.01857
1981	30.62806
1982	35.44931
1983	32.2887
1984	28.00503
1985	26.37806
1986	28.81145
1987	30.56124
1988	27.40434
1989	25.91604
1990	24.34255
1991	18.15887
1992	17.32569
1993	17.20643
1994	19.23073
1995	21.35874
1996	17.94589
1997	20.58034
1998	19.20354
1999	24.01225
2000	24.53228
2001	25.42563
2002	24.12493
2003	26.74829
2004	31.50262
2005	32.09063
2006	25.60023
2007	23.5662
2008	29.77571
2009	31.73423
2010	35.19324
2011	27.20242
2012	27.39357
2013	26.22212
2014	22.45884
2015	22.20889
2016	21.86138
2017	21.00189
2018	19.8716
2019	20.00405
2020	21.24401
2021	22.41874
2022	22.55027