Year	% (national estimate)
1965	50.65
1975	56.71
1992	50.36
1997	29.6
2000	25.643
2001	32.565
2002	28.597
2003	25.694
2004	25.629
2005	24.533
2006	26.361
2007	25.959
2008	26.08
2009	24.815
2010	26.591
2011	24.813
2012	25.311
2013	24.698
2014	22.65
2015	21.169
2016	19.558
2017	21.836
2018	19.305
2019	20.051
2020	18.235
2021	15.506
2022	18.067
2023	18.192