Year	Percent
1991	52.802
1992	52.46
1993	52.091
1994	53.088
1995	51.272
1996	51.649
1997	48.354
1998	47.932
1999	48.53
2000	49.42
2001	50.027
2002	49.125
2003	46.481
2004	46.226
2005	46.178
2006	46.962
2007	45.235
2008	44.856
2009	44.339
2010	44.21
2011	43.162
2012	43.853
2013	43.605
2014	43.618
2015	42.774
2016	42.202
2017	43.923
2018	43.818
2019	43.712
2020	43.605
2021	43.5
2022	43.394