Year	Percent
1991	58.068
1992	56.903
1993	56.75
1994	56.587
1995	56.397
1996	56.207
1997	54.371
1998	55.457
1999	55.933
2000	55.157
2001	55.683
2002	54.03
2003	53.625
2004	52.129
2005	50.101
2006	49.628
2007	49.655
2008	50.713
2009	51.47
2010	50.813
2011	50.471
2012	51.791
2013	51.664
2014	49.852
2015	46.443
2016	48.553
2017	47.966
2018	47.319
2019	46.744
2020	46.259
2021	45.87
2022	45.563