Year	Percent
1991	50.27
1992	50.042
1993	49.888
1994	49.69
1995	49.43
1996	50.225
1997	51.104
1998	52.09
1999	53.269
2000	54.46
2001	56.637
2002	58.938
2003	61.051
2004	62.201
2005	62.946
2006	63.701
2007	63.746
2008	63.925
2009	63.36
2010	61.837
2011	59.235
2012	62.088
2013	55.991
2014	52.92
2015	55.819
2016	55.661
2017	56.134
2018	56.569
2019	56.955
2020	57.323
2021	57.662
2022	57.953