Year	Percent
1990	99.039
1991	99.04
1992	99.033
1993	99.03
1994	99.018
1995	99.013
1996	99.041
1997	99.068
1998	99.091
1999	99.112
2000	99.133
2001	99.144
2002	99.159
2003	99.176
2004	99.196
2005	99.22
2006	99.085
2007	98.912
2008	98.679
2009	98.398
2010	98.398
2011	98.365
2012	98.324
2013	98.283
2014	98.246
2015	98.216
2016	98.18
2017	98.1
2018	98.025
2019	97.952
2020	97.886
2021	97.807
2022	97.728
2023	97.653
2024	97.59
2025	97.543
2026	97.482
2027	97.432
2028	97.391
2029	97.355
2030	97.324