Year	% (national estimate)
1960	42.8
1961	43.1927354049274
1962	43.3
1963	42.9
1964	43.3
1965	44
1966	46.5
1967	47.6
1968	48.5
1969	50.400000000000006
1970	51.30196188345501
1971	50.91861778203537
1972	53
1973	54.9
1974	56.6
1975	57.2
1976	58.020318637650675
1977	59.5654276483498
1978	61.568704333388865
1979	62.48723425181458
1980	62.103800595497596
1981	62.19912567197694
1982	62.18593409054033
1983	62.163450881032695
1984	63.02413626511716
1985	63.914405627408975
1986	64.57616603400999
1987	64.88676959145184
1988	64.84503112704115
1989	64.79816872251048
1990	63.335895795226484
1991	62.12865788520381
1992	62.06025427391125
1993	62.02368441989857
1994	62.65636233039452
1995	62.373914963058645
1996	62.195516493215386
1997	62.567320723695815
1998	63.030172420919364
1999	62.77953950240758
2000	62.986429775192065
2001	62.11947564844155
2002	61.45360697707236
2003	59.91315100312003
2004	59.361811552507646
2005	59.249442113665815
2006	58.74903902388233
2007	58.18569901628516
2008	57.583307133665336
2009	56.284928814563926
2010	54.727300250870215
2011	54.44829659446233
2012	54.35894135416895
2013	54.605870644355164
2014	54.71605667996209
2015	54.882503717091254
2016	54.83865212374996
2017	55.27370470894189
2018	55.46236758782769
2019	56.187730936928396
2020	54.03505647209933
2021	55.43219513942024
2022	55.70848573994637
2023	56.78481948140037