Year	Percent
1991	37.276
1992	36.533
1993	36.56
1994	35.738
1995	34.626
1996	34.426
1997	33.846
1998	34.246
1999	33.406
2000	33.077
2001	32.697
2002	32.414
2003	31.796
2004	31.299
2005	30.937
2006	30.797
2007	30.079
2008	29.911
2009	28.978
2010	28.359
2011	29.513
2012	29.264
2013	30.001
2014	30.852
2015	30.079
2016	30.988
2017	30.757
2018	30.565
2019	30.297
2020	29.942
2021	29.55
2022	29.137