Year	Percent
1991	88.903
1992	88.777
1993	88.625
1994	90.644
1995	90.759
1996	90.411
1997	90.313
1998	89.881
1999	89.014
2000	88.888
2001	88.769
2002	88.231
2003	80.316
2004	80.377
2005	79.129
2006	78.423
2007	76.921
2008	75.995
2009	75.607
2010	74.992
2011	74.642
2012	74.336
2013	73.793
2014	73.576
2015	72.944
2016	72.726
2017	72.696
2018	72.63
2019	72.558
2020	72.484
2021	72.408
2022	72.334