Year	Percent
1991	40.273
1992	43.953
1993	45.81
1994	44
1995	46.19
1996	42.402
1997	45.036
1998	45.795
1999	47.587
2000	47.954
2001	47.444
2002	40.069
2003	39.604
2004	32.998
2005	33.055
2006	31.425
2007	31.006
2008	30.394
2009	30.711
2010	32.355
2011	31.09
2012	31.013
2013	30.354
2014	29.31
2015	25.609
2016	22.638
2017	22.269
2018	21.464
2019	20.958
2020	20.299
2021	19.933
2022	19.51