Year	Percent
1991	57.532
1992	57.198
1993	57.173
1994	55.59
1995	56.976
1996	57.681
1997	51.456
1998	49.284
1999	48.609
2000	51.685
2001	58.854
2002	61
2003	58.48
2004	59.704
2005	59.1
2006	60.735
2007	62.032
2008	62.063
2009	62.284
2010	61.311
2011	61.396
2012	60.296
2013	59.53
2014	59.051
2015	59.517
2016	59.219
2017	58.012
2018	57.888
2019	57.883
2020	57.826
2021	57.737
2022	57.678