Year	% (national estimate)
1961	30.519400024792365
1971	34.992437783583114
1977	44.00794213586725
1978	44.22060294327761
1979	45.59689699755782
1980	46.74761491760624
1981	48.15297696653629
1982	47.77647747220596
1983	48.831843490515205
1984	49.05451271039689
1985	49.51301404073478
1986	51.43793127483097
1987	52.1357083701801
1988	53.42036995262802
1989	54.914639716797986
1990	54.84465922250976
1991	55.84997730367681
1992	54.61958107240796
1993	54.27066164351307
1994	55.180372585165536
1995	55.944874113017185
1996	56.89385066999254
1997	57.558095296069155
1998	58.432383262583386
1999	59.847691864257655
2000	60.605279126213595
2001	61.865154187701485
2002	62.54867630633621
2003	63.1202375952481
2004	65.25845450333996
2005	65.55495136245545
2006	66.06087180029937
2007	66.13072193122296
2008	67.47357085437807
2009	67.60492084918396
2010	68.06067807595562
2011	68.87650019357335
2012	70.58760454642935
2013	71.24793503265352
2014	72.01021727088079
2015	71.21033718174172
2016	71.97635647165808
2017	72.63921787540923
2018	72.88059027254931
2019	73.47188448700328
2020	72.54877747591998
2021	73.22027609875246
2022	73.6474827833682
2023	70.61936362089502