Year	Percent
1990	92.99
1991	92.656
1992	92.31
1993	91.951
1994	91.581
1995	91.2
1996	90.883
1997	90.564
1998	90.237
1999	89.893
2000	89.522
2001	89.553
2002	89.572
2003	89.578
2004	89.573
2005	89.557
2006	89.494
2007	89.418
2008	89.355
2009	89.299
2010	89.305
2011	89.284
2012	89.293
2013	89.313
2014	89.348
2015	89.393
2016	89.441
2017	89.487
2018	89.535
2019	89.583
2020	89.628
2021	89.668
2022	89.705
2023	89.74
2024	89.773
2025	89.806
2026	89.836
2027	89.866
2028	89.894
2029	89.917
2030	89.934