Year	Percent
1991	57.901
1992	55.538
1993	52.931
1994	52.109
1995	51.705
1996	53.42
1997	53.696
1998	53.765
1999	53.3
2000	53.57
2001	52.884
2002	53.684
2003	52.443
2004	53.103
2005	52.496
2006	52.275
2007	51.077
2008	50.546
2009	47.799
2010	46.136
2011	45.166
2012	45.775
2013	45.817
2014	47.447
2015	49.31
2016	50.612
2017	50.767
2018	51.126
2019	50.959
2020	50.531
2021	50.011
2022	49.427