Year	Percent
1991	55.675
1992	54.542
1993	54.207
1994	56.962
1995	59.211
1996	59.268
1997	57.731
1998	58.523
1999	59.534
2000	60.779
2001	60.545
2002	60.17
2003	61.18
2004	61.551
2005	62.356
2006	62.856
2007	63.21
2008	63.479
2009	60.689
2010	59.695
2011	60.124
2012	59.379
2013	58.643
2014	57.909
2015	58.747
2016	58.748
2017	58.542
2018	58.364
2019	58.023
2020	57.876
2021	57.679
2022	57.449