Year	Percent
1991	51.893
1992	51.706
1993	51.614
1994	51.741
1995	51.491
1996	51.349
1997	50.995
1998	50.674
1999	50.31
2000	49.63
2001	49.291
2002	48.933
2003	48.586
2004	48.282
2005	48.019
2006	47.835
2007	47.765
2008	47.754
2009	47.725
2010	47.716
2011	47.754
2012	47.794
2013	47.824
2014	47.895
2015	47.99
2016	48.047
2017	48.133
2018	48.214
2019	48.285
2020	48.343
2021	48.37
2022	48.389