Year	Percent
1991	48.127
1992	47.577
1993	47.513
1994	47.389
1995	47.488
1996	47.702
1997	47.693
1998	47.616
1999	47.521
2000	47.427
2001	47.262
2002	47.066
2003	46.776
2004	46.458
2005	46.146
2006	45.762
2007	45.436
2008	45.028
2009	44.633
2010	44.384
2011	43.957
2012	43.571
2013	43.252
2014	43.079
2015	42.5
2016	41.935
2017	41.826
2018	41.717
2019	41.609
2020	41.507
2021	41.409
2022	41.318