Year	Percent
1990	97.736
1991	97.846
1992	97.956
1993	97.587
1994	97.368
1995	97.673
1996	97.383
1997	97.01
1998	97.038
1999	97.196
2000	96.581
2001	96.102
2002	95.988
2003	95.552
2004	95.665
2005	95.634
2006	95.501
2007	95.855
2008	95.9
2009	96.025
2010	94.667
2011	95.129
2012	95.162
2013	94.756
2014	95.076
2015	95.502
2016	95.566
2017	95.48
2018	95.395
2019	95.313
2020	95.236
2021	95.165
2022	95.1
2023	95.039
2024	94.977
2025	94.913
2026	94.845
2027	94.772
2028	94.695
2029	94.613
2030	94.525