Year	Percent
1990	97.322
1991	97.308
1992	97.294
1993	97.28
1994	97.268
1995	97.257
1996	97.255
1997	97.255
1998	97.257
1999	97.26
2000	97.263
2001	97.273
2002	97.282
2003	97.29
2004	97.297
2005	97.304
2006	97.296
2007	97.289
2008	97.284
2009	97.28
2010	97.278
2011	97.284
2012	97.292
2013	97.3
2014	97.307
2015	97.315
2016	97.316
2017	97.315
2018	97.313
2019	97.31
2020	97.306
2021	97.302
2022	97.298
2023	97.293
2024	97.288
2025	97.283
2026	97.279
2027	97.275
2028	97.271
2029	97.268
2030	97.266