Year	Percent
1991	91.512
1992	91.221
1993	91.456
1994	91.182
1995	90.176
1996	90.008
1997	89.871
1998	89.453
1999	89.39
2000	89.197
2001	89.033
2002	88.806
2003	88.237
2004	88.159
2005	88.378
2006	88.174
2007	90.905
2008	90.866
2009	90.954
2010	90.8
2011	90.8
2012	91.222
2013	91.021
2014	91.078
2015	89.918
2016	89
2017	88.813
2018	88.761
2019	88.71
2020	88.658
2021	88.609
2022	88.559