Year	Percent
1991	90.735
1992	91.015
1993	89.98
1994	90.025
1995	89.604
1996	89.367
1997	89.218
1998	89.622
1999	88.553
2000	88.643
2001	88.249
2002	88.29
2003	88.224
2004	88.615
2005	89.638
2006	90.313
2007	90.375
2008	89.836
2009	89.996
2010	90.162
2011	89.994
2012	90.053
2013	90.09
2014	90.051
2015	90.039
2016	89.989
2017	89.955
2018	89.939
2019	89.893
2020	89.85
2021	89.804
2022	89.744