Year	Percent
1991	57.538
1992	55.054
1993	53.189
1994	53.351
1995	53.26
1996	52.072
1997	50.182
1998	51.967
1999	53.778
2000	55.716
2001	56.171
2002	57.563
2003	58.557
2004	58.179
2005	58.717
2006	59.371
2007	59.859
2008	60.134
2009	57.39
2010	56.806
2011	56.468
2012	55.471
2013	55.911
2014	56.872
2015	57.194
2016	56.806
2017	57.719
2018	58.234
2019	58.171
2020	57.997
2021	57.765
2022	57.503