Year	Percent
1991	34.411
1992	34.028
1993	35.11
1994	34.465
1995	35.314
1996	35.864
1997	36.522
1998	38.325
1999	35.936
2000	34.893
2001	34.98
2002	34.728
2003	34.81
2004	34.449
2005	34.426
2006	33.453
2007	34.1
2008	32.817
2009	32.947
2010	33.543
2011	33.655
2012	34.464
2013	34.998
2014	35.226
2015	35.815
2016	35.745
2017	35.203
2018	35.258
2019	35.532
2020	35.845
2021	36.258
2022	36.733