Year	Percent
1991	52.48
1992	52.233
1993	52.012
1994	52.488
1995	51.87
1996	51.757
1997	50.506
1998	49.654
1999	49.083
2000	48.817
2001	49.383
2002	49.327
2003	48.908
2004	48.089
2005	47.461
2006	47.269
2007	46.802
2008	46.346
2009	45.857
2010	45.408
2011	44.663
2012	44.307
2013	43.903
2014	43.792
2015	43.396
2016	42.987
2017	43.811
2018	43.748
2019	43.684
2020	43.62
2021	43.557
2022	43.494