Year	Percent
1990	94.512
1991	94.281
1992	94.027
1993	93.272
1994	91.911
1995	91.874
1996	92.825
1997	92.529
1998	91.984
1999	92.783
2000	91.53
2001	91.45
2002	91.855
2003	92.048
2004	91.27
2005	91.702
2006	92.282
2007	92.328
2008	93.245
2009	92.164
2010	92.01
2011	91.524
2012	90.65
2013	90.179
2014	90.328
2015	90.828
2016	90.78
2017	90.698
2018	90.618
2019	90.545
2020	90.482
2021	90.432
2022	90.394
2023	90.367
2024	90.347
2025	90.329
2026	90.316
2027	90.308
2028	90.303
2029	90.294
2030	90.278