Year	Percent
1991	54.49
1992	54.406
1993	54.363
1994	53.896
1995	53.993
1996	53.069
1997	52.313
1998	52.646
1999	52.772
2000	52.653
2001	52.428
2002	52.089
2003	52.344
2004	51.605
2005	50.241
2006	49.384
2007	48.234
2008	48.018
2009	47.692
2010	47.533
2011	47.853
2012	46.891
2013	46.641
2014	45.795
2015	45.616
2016	45.488
2017	45.391
2018	45.318
2019	45.242
2020	45.161
2021	45.081
2022	44.998