Year	Percent
1991	49.246
1992	49.399
1993	49.301
1994	49.411
1995	49.514
1996	49.807
1997	50.143
1998	50.485
1999	50.803
2000	51.107
2001	51.357
2002	51.538
2003	51.727
2004	52
2005	52.355
2006	53.032
2007	53.733
2008	54.498
2009	55.233
2010	55.95
2011	56.646
2012	57.327
2013	57.967
2014	57.327
2015	56.793
2016	56.149
2017	56.321
2018	56.493
2019	56.668
2020	56.84
2021	57.009
2022	57.174