Year	Percent
1990	86.247
1991	86.404
1992	86.589
1993	86.773
1994	86.91
1995	86.975
1996	86.969
1997	86.869
1998	86.712
1999	86.48
2000	86.272
2001	86.058
2002	85.84
2003	85.633
2004	85.464
2005	85.339
2006	84.664
2007	83.936
2008	83.129
2009	82.223
2010	81.21
2011	80.093
2012	81.487
2013	81.549
2014	81.609
2015	81.678
2016	81.737
2017	81.624
2018	81.504
2019	81.375
2020	81.236
2021	81.093
2022	80.942
2023	80.787
2024	80.627
2025	80.461
2026	80.294
2027	80.122
2028	79.948
2029	79.773
2030	79.599