Year	Percent
1991	55.787
1992	55.395
1993	54.967
1994	54.859
1995	54.405
1996	54.045
1997	53.303
1998	53.068
1999	52.773
2000	52.172
2001	51.711
2002	51.289
2003	50.762
2004	50.488
2005	50.016
2006	49.367
2007	48.714
2008	48.297
2009	48.076
2010	47.616
2011	47.232
2012	46.62
2013	45.764
2014	45.498
2015	45.158
2016	44.812
2017	44.944
2018	44.858
2019	44.771
2020	44.685
2021	44.601
2022	44.516