Year	Percent
1991	28.899
1992	28.126
1993	25.843
1994	23.934
1995	22.475
1996	22.498
1997	21.836
1998	22.639
1999	19.378
2000	20.599
2001	21.657
2002	19.822
2003	18.522
2004	18.367
2005	19.726
2006	21.16
2007	22.469
2008	23.807
2009	23.288
2010	22.177
2011	20.041
2012	19.933
2013	19.663
2014	21.605
2015	21.608
2016	23.986
2017	24.508
2018	24.529
2019	23.975
2020	23.482
2021	22.881
2022	22.181