Year	Percent
1991	91.233
1992	91.238
1993	91.268
1994	91.926
1995	91.779
1996	91.839
1997	91.469
1998	91.486
1999	90.813
2000	90.532
2001	90.76
2002	90.693
2003	90.577
2004	90.103
2005	90.205
2006	89.68
2007	89.037
2008	89.685
2009	89.22
2010	89.32
2011	89.266
2012	89.05
2013	88.696
2014	88.477
2015	88.108
2016	87.952
2017	87.891
2018	87.831
2019	87.773
2020	87.714
2021	87.656
2022	87.596