Year	Percent
1966	22.67536
1967	22.85433
1968	21.87003
1969	21.40095
1970	21.85881
1971	21.51435
1972	22.28799
1973	23.8786
1974	30.51495
1975	30.35538
1976	29.68126
1977	29.30481
1978	28.47916
1979	26.37766
1995	34.95967
1996	33.4309
1997	33.79807
1998	33.24276
1999	33.27966
2000	30.87872
2001	29.85131
2002	34.14251
2003	32.02979
2004	31.42051
2005	30.76273
2006	30.18227
2007	28.06701
2008	27.05257
2009	30.46515
2010	29.0781
2011	29.05021
2012	28.00061
2013	26.49303
2014	25.84538
2015	25.74335
2016	25.13345
2017	24.55014
2018	23.97338
2019	22.95625
2020	24.69294
2021	23.18822
2022	21.8883