Year	Percent
1990	98.011
1991	97.682
1992	97.693
1993	97.609
1994	97.681
1995	97.365
1996	97.065
1997	97.009
1998	96.851
1999	96.549
2000	96.238
2001	95.891
2002	95.496
2003	95.249
2004	95.304
2005	94.896
2006	94.777
2007	94.768
2008	94.461
2009	94.494
2010	94.387
2011	94.444
2012	94.659
2013	94.864
2014	94.416
2015	94.37
2016	94.273
2017	94.264
2018	94.256
2019	94.247
2020	94.233
2021	94.218
2022	94.197
2023	94.174
2024	94.15
2025	94.128
2026	94.109
2027	94.092
2028	94.073
2029	94.047
2030	94.008
