Year	% (national estimate)
1960	56.1
1961	55.4
1962	55.5
1963	55.4
1964	55.7
1965	56.2
1966	56.9
1967	57.3
1968	57.5
1969	58
1970	57.4
1971	56.6
1972	57
1973	57.800000000000004
1974	57.800000000000004
1975	56.1
1976	56.83291233738206
1977	57.801752578743184
1978	59.12519970664275
1979	59.80147185814704
1980	59.22193280149839
1981	59.10597262731085
1982	57.7498021638147
1983	57.80660560965421
1984	59.320218646043955
1985	59.96757324053019
1986	60.607909329440794
1987	61.41200457871769
1988	62.23650461379113
1989	62.91845402843247
1990	62.68758100851902
1991	61.499107079039305
1992	61.181839442722904
1993	61.31748579283355
1994	62.156061512700646
1995	62.51734549590409
1996	62.742235461881705
1997	63.35290541290522
1998	63.62481563769797
1999	63.88166067761492
2000	64.08361122627257
2001	63.40941900392723
2002	62.631343456520845
2003	62.29392403615909
2004	62.37473317335443
2005	62.680361801642654
2006	63.0910904178653
2007	63.01961408217801
2008	62.296692391003205
2009	59.553945932887444
2010	58.792353027728375
2011	58.724633875946104
2012	58.906121498626014
2013	58.942561283297984
2014	59.28146805868899
2015	59.574902763314476
2016	59.89034078772406
2017	60.29000391247042
2018	60.583038622492886
2019	60.94402920727086
2020	56.91336029118427
2021	58.58456127074094
2022	60.18147964050031
2023	60.51595727023673