Year	% (national estimate)
1997	34.191
1998	33.265
1999	31.867
2000	31.112
2001	29.973
2002	25.818
2003	23.208
2004	25.744
2005	21.585
2006	20.641
2007	20.242
2008	20.171
2009	20.59
2010	19.902
2011	19.697
2012	19.593
2013	18.619
2014	18.037
2015	19.296
2016	17.066
2017	20.365
2018	20.26
2019	19.261
2020	19.722
2021	16.083
2022	14.307
2023	13.657