Year	Percent
1991	49.568
1992	49.658
1993	49.076
1994	48.76
1995	48.427
1996	48.41
1997	48.712
1998	48.186
1999	47.417
2000	47.07
2001	46.86
2002	46.096
2003	46.094
2004	46.168
2005	46.332
2006	46.548
2007	46.758
2008	46.726
2009	46.473
2010	46.49
2011	46.291
2012	46.331
2013	47.231
2014	47.814
2015	48.346
2016	49.163
2017	49.153
2018	49.259
2019	49.224
2020	49.107
2021	49.041
2022	48.986