Year	Percent
1991	31.764
1992	32.057
1993	32.349
1994	32.686
1995	34.518
1996	32.359
1997	31.564
1998	30.896
1999	30.791
2000	32.809
2001	32.346
2002	30.93
2003	31.247
2004	32.511
2005	32.868
2006	33.468
2007	34.006
2008	35.552
2009	34.448
2010	32.642
2011	32.891
2012	33.123
2013	34.075
2014	34.009
2015	34.635
2016	33.931
2017	33.731
2018	33.747
2019	33.65
2020	33.839
2021	33.981
2022	34.097