Year	Percent
1991	38.625
1992	39.813
1993	40.114
1994	39.924
1995	40.443
1996	40.931
1997	41.652
1998	42.032
1999	42.449
2000	42.735
2001	42.767
2002	43.276
2003	42.95
2004	43.2
2005	44.19
2006	45.268
2007	46.478
2008	45.054
2009	43.339
2010	45.874
2011	47.126
2012	47.263
2013	46.946
2014	48.165
2015	49.103
2016	49.999
2017	50.045
2018	50.056
2019	50.064
2020	50.056
2021	50.074
2022	50.091