Year	Percent
1990	98.04
1991	97.982
1992	97.874
1993	97.761
1994	97.643
1995	97.519
1996	97.391
1997	97.257
1998	97.116
1999	96.968
2000	96.81
2001	96.641
2002	96.463
2003	96.273
2004	96.074
2005	95.865
2006	95.646
2007	95.068
2008	94.416
2009	93.683
2010	92.859
2011	91.933
2012	90.895
2013	89.733
2014	88.431
2015	88.398
2016	88.345
2017	88.292
2018	88.237
2019	88.182
2020	88.125
2021	88.069
2022	88.011
2023	87.953
2024	87.894
2025	87.833
2026	87.77
2027	87.706
2028	87.643
2029	87.579
2030	87.516