Year	Percent
1991	56.681
1992	56.193
1993	55.385
1994	55.156
1995	54.458
1996	54.996
1997	54.703
1998	54.251
1999	53.689
2000	53.624
2001	53.421
2002	53.56
2003	53.307
2004	53.195
2005	53.125
2006	54.064
2007	53.53
2008	53.062
2009	52.615
2010	51.687
2011	51.238
2012	50.775
2013	50.001
2014	49.193
2015	48.373
2016	47.682
2017	47.547
2018	47.379
2019	47.209
2020	47.043
2021	46.878
2022	46.712