Year	Percent
1991	45.743
1992	45.725
1993	45.556
1994	45.585
1995	34.441
1996	38.025
1997	34.822
1998	34.804
1999	34.583
2000	34.525
2001	33.902
2002	33.67
2003	33.43
2004	33.229
2005	33.063
2006	31.232
2007	31.181
2008	31.311
2009	31.236
2010	31.322
2011	31.4
2012	31.226
2013	31.126
2014	31.117
2015	30.907
2016	29.874
2017	30.043
2018	29.937
2019	29.807
2020	29.73
2021	29.656
2022	29.586