Year	Percent
1991	35.065
1992	34.675
1993	34.27
1994	34.339
1995	34.082
1996	33.898
1997	34.114
1998	34.765
1999	35.024
2000	34.885
2001	35.115
2002	35.554
2003	35.654
2004	36.595
2005	37.035
2006	37.563
2007	33.104
2008	29.474
2009	27.404
2010	25.831
2011	24.426
2012	24.156
2013	24.382
2014	24.686
2015	24.597
2016	24.767
2017	24.849
2018	25.258
2019	25.679
2020	26.073
2021	26.477
2022	26.843