Year	Percent
1991	31.068
1992	36.911
1993	33.359
1994	30.428
1995	30.541
1996	32.471
1997	33.385
1998	35.588
1999	34.911
2000	30.315
2001	32.284
2002	32.75
2003	30.61
2004	30.177
2005	33.027
2006	31.851
2007	32.295
2008	35.032
2009	32.835
2010	34.275
2011	33.464
2012	32.952
2013	32.343
2014	31.02
2015	30.473
2016	30.278
2017	30.181
2018	30.073
2019	29.94
2020	29.826
2021	29.722
2022	29.631