Year	Percent
1965	64.58408
1966	68.69301
1967	66.23538
1968	67.3916
1969	66.42455
1970	66.86816
1971	66.83822
1972	67.84646
1973	65.33253
1974	68.41818
1975	69.00609
1976	66.08601
1977	60.12153
1978	58.86884
1979	60.16205
1980	57.89902
1981	56.79862
1982	57.16729
1983	56.52251
1984	57.29881
1985	48.85803
1986	48.69715
1987	47.95033
1988	47.79211
1989	47.68957
1990	48.80289
1991	44.72339
1992	42.66526
1993	39.89595
1994	40.44171
1995	39.04141
1996	38.92766
1997	38.78073
1998	37.39301
1999	38.70148
2000	38.2439
2001	35.24767
2002	36.1503
2003	35.10588
2004	34.67636
2005	33.8249
2006	32.36649
2007	31.16441
2008	30.30572
2009	31.32265
2010	33.17938
2011	30.80549
2012	30.07606
2013	28.62266
2014	27.4619
2015	26.51851
2016	25.51788
2017	23.69955
2018	22.33467
2019	21.58337
2020	22.18009
2021	22.02145
2022	21.06075