Year	% (national estimate)
1981	45.86099911606698
1983	46.468008650734866
1984	48.71993903939064
1985	48.3898176385568
1986	48.174441832702755
1987	49.02620214715128
1988	48.82582316138891
1989	48.30463661106192
1990	47.881732031076034
1991	46.35575155674349
1992	44.41387555564695
1993	42.71079823056132
1994	41.62818604458359
1995	40.735623542271966
1996	39.549352459165505
1997	39.042176874974466
1998	39.560968584023215
1999	40.43028476274514
2000	40.63905983522825
2001	39.97203567664849
2002	39.943828568266206
2003	39.83785463370065
2004	39.560391945167495
2005	39.24911956495543
2006	39.32263406695501
2007	39.87496253261138
2008	39.81384532366132
2009	39.42765647513941
2010	38.394031136539326
2011	38.164272382531834
2012	37.74220571181195
2013	37.832463146072136
2014	37.14378206326825
2015	36.77094380659852
2016	36.858009071734564
2017	37.035299849657655
2018	36.84822793695587
2019	36.933716288228936
2020	35.32425605516661
2021	38.057993862994046
2022	39.41088243191025
2023	40.2790187849428