Year	Percent
1991	87.748
1992	87.546
1993	86.652
1994	85.618
1995	84.538
1996	84.776
1997	82.883
1998	82.503
1999	81.954
2000	81.335
2001	80.924
2002	85.595
2003	84.585
2004	84
2005	82.625
2006	81.223
2007	80.178
2008	79.345
2009	51.284
2010	50.616
2011	49.394
2012	48.477
2013	47.718
2014	47.283
2015	46.32
2016	45.432
2017	45.364
2018	45.255
2019	45.146
2020	45.037
2021	44.926
2022	44.815