Year	Percent
1991	47.05
1992	47.35
1993	47.792
1994	48.208
1995	48.609
1996	48.889
1997	49.309
1998	49.767
1999	50.119
2000	50.395
2001	50.722
2002	50.927
2003	51.1
2004	50.091
2005	50.281
2006	50.292
2007	50.25
2008	50.18
2009	49.824
2010	49.27
2011	49.05
2012	48.901
2013	48.755
2014	48.751
2015	48.695
2016	48.567
2017	48.369
2018	48.187
2019	48.061
2020	47.913
2021	47.729
2022	47.528