Year	Percent
1991	39.047
1992	39.784
1993	41.732
1994	44.268
1995	45.781
1996	46.165
1997	45.454
1998	45.38
1999	46.265
2000	47.296
2001	47.061
2002	46.322
2003	46.549
2004	46.991
2005	48.646
2006	49.308
2007	50.413
2008	51.556
2009	51.616
2010	52.495
2011	52.847
2012	53.92
2013	54.503
2014	55.536
2015	55.808
2016	56.438
2017	56.774
2018	57.004
2019	57.021
2020	57.04
2021	57.079
2022	57.134