Year	Percent
1991	59.896
1992	57.834
1993	54.643
1994	52.408
1995	50.69
1996	48.974
1997	47.969
1998	48.878
1999	49.689
2000	49.393
2001	48.935
2002	46.923
2003	45.133
2004	42.853
2005	43.942
2006	45.681
2007	47.805
2008	49.331
2009	48.064
2010	48.299
2011	49.544
2012	48.254
2013	48.144
2014	47.569
2015	46.929
2016	47.358
2017	47.431
2018	47.504
2019	47.66
2020	47.68
2021	47.625
2022	47.533