Year	Percent
1990	93.571
1991	93.54
1992	93.489
1993	93.437
1994	93.363
1995	93.291
1996	93.233
1997	93.182
1998	93.23
1999	93.141
2000	92.784
2001	92.5
2002	91.796
2003	91.044
2004	90.158
2005	89.061
2006	87.804
2007	86.321
2008	84.662
2009	82.927
2010	81.179
2011	80.921
2012	80.836
2013	80.905
2014	80.85
2015	80.775
2016	80.625
2017	80.46
2018	80.259
2019	80.024
2020	79.762
2021	79.484
2022	79.178
2023	78.897
2024	78.71
2025	78.647
2026	78.703
2027	78.875
2028	79.1
2029	79.279
2030	79.355