Year	Percent
1991	34.758
1992	34.159
1993	35.208
1994	34.997
1995	35.319
1996	34.719
1997	39.025
1998	42.221
1999	43.607
2000	44.603
2001	44.033
2002	44.303
2003	44.644
2004	44.869
2005	44.84
2006	44.899
2007	46.054
2008	45.848
2009	45.407
2010	45.741
2011	46.286
2012	45.05
2013	45.389
2014	45.264
2015	45.006
2016	44.95
2017	45.347
2018	45.171
2019	45.011
2020	44.941
2021	44.816
2022	44.696