Year	Percent
1991	45.319
1992	45.056
1993	45.776
1994	45.621
1995	45.464
1996	45.202
1997	44.881
1998	43.967
1999	43.368
2000	43.341
2001	42.514
2002	41.82
2003	41.606
2004	40.304
2005	39.909
2006	39.193
2007	42.017
2008	45.212
2009	47.651
2010	49.036
2011	49.3
2012	49.773
2013	49.672
2014	49.516
2015	49.732
2016	49.338
2017	49.159
2018	48.498
2019	47.827
2020	47.16
2021	46.457
2022	45.75