Year	Percent
1990	92.723
1991	92.709
1992	92.685
1993	92.658
1994	92.642
1995	92.563
1996	92.57
1997	92.593
1998	92.532
1999	92.438
2000	92.359
2001	92.269
2002	92.196
2003	92.179
2004	92.255
2005	92.257
2006	92.295
2007	92.451
2008	92.358
2009	92.303
2010	92.212
2011	92.141
2012	92.135
2013	92.274
2014	92.221
2015	92.107
2016	91.994
2017	91.967
2018	91.936
2019	91.902
2020	91.865
2021	91.825
2022	91.784
2023	91.744
2024	91.708
2025	91.677
2026	91.652
2027	91.633
2028	91.619
2029	91.607
2030	91.597