Year	Percent
1991	35.494
1992	37.36
1993	38.826
1994	40.495
1995	41.145
1996	41.618
1997	41.94
1998	42.215
1999	43.276
2000	43.849
2001	43.996
2002	44.377
2003	44.96
2004	45.389
2005	45.744
2006	45.644
2007	45.27
2008	45.303
2009	46.74
2010	47.006
2011	46.747
2012	46.742
2013	47.528
2014	47.312
2015	46.951
2016	47.139
2017	47.299
2018	47.708
2019	48.024
2020	48.25
2021	48.459
2022	48.655