Year	Percent
1991	47.627
1992	48.008
1993	47.701
1994	47.861
1995	47.916
1996	48.096
1997	48.101
1998	48.293
1999	48.965
2000	49.174
2001	49.144
2002	49.351
2003	49.433
2004	49.671
2005	49.916
2006	49.804
2007	49.342
2008	49.57
2009	49.76
2010	49.522
2011	49.55
2012	49.735
2013	49.897
2014	50.171
2015	50.455
2016	50.894
2017	51.109
2018	51.288
2019	51.447
2020	51.556
2021	51.598
2022	51.581