Year	Percent
1991	43.606
1992	43.406
1993	45.618
1994	45.665
1995	45.896
1996	44.908
1997	45.43
1998	46.09
1999	45.738
2000	45.928
2001	45.378
2002	44.659
2003	44.502
2004	44.939
2005	46.447
2006	46.856
2007	46.731
2008	47.401
2009	48.055
2010	48.769
2011	48.653
2012	46.609
2013	46.406
2014	47.399
2015	48.691
2016	49.569
2017	49.858
2018	50.292
2019	50.92
2020	51.492
2021	52.028
2022	52.492