Year	Percent
1991	34.127
1992	33.919
1993	33.357
1994	33.791
1995	34.517
1996	34.023
1997	34.948
1998	34.22
1999	33.42
2000	32.657
2001	32.781
2002	33.163
2003	33.256
2004	32.054
2005	32.315
2006	32.349
2007	32.994
2008	33.023
2009	32.219
2010	31.209
2011	31.852
2012	31.742
2013	31.994
2014	32.179
2015	31.695
2016	30.783
2017	30.785
2018	30.819
2019	30.846
2020	30.798
2021	30.735
2022	30.701