Year	Percent
1990	94.607
1991	94.948
1992	94.834
1993	94.734
1994	94.593
1995	94.524
1996	94.31
1997	93.985
1998	93.478
1999	92.231
2000	92.127
2001	91.683
2002	91.773
2003	91.931
2004	91.632
2005	91.244
2006	90.868
2007	90.573
2008	90.53
2009	90.051
2010	90.305
2011	90.514
2012	90.658
2013	90.686
2014	91.346
2015	91.099
2016	91.122
2017	91.007
2018	90.872
2019	90.747
2020	90.653
2021	90.587
2022	90.551
2023	90.541
2024	90.547
2025	90.56
2026	90.584
2027	90.62
2028	90.663
2029	90.701
2030	90.728