Year	Percent
1990	93.408
1991	93.606
1992	92.559
1993	92.284
1994	92.617
1995	92.59
1996	92.654
1997	93.493
1998	93.489
1999	93.377
2000	93.838
2001	93.978
2002	93.821
2003	93.66
2004	93.733
2005	93.815
2006	94.132
2007	94.039
2008	94.527
2009	94.44
2010	93.338
2011	93.012
2012	92.969
2013	92.248
2014	92.184
2015	92.073
2016	91.724
2017	91.707
2018	91.693
2019	91.682
2020	91.673
2021	91.667
2022	91.662
2023	91.658
2024	91.652
2025	91.643
2026	91.631
2027	91.613
2028	91.594
2029	91.574
2030	91.558