Year	Percent
1990	90.518
1991	90.516
1992	90.507
1993	90.497
1994	90.491
1995	90.474
1996	90.486
1997	88.915
1998	91.447
1999	91.102
2000	90.671
2001	91.517
2002	91.617
2003	90.647
2004	91.042
2005	91.004
2006	90.993
2007	91.246
2008	91.528
2009	91.222
2010	91.725
2011	91.765
2012	92.308
2013	92.557
2014	92.25
2015	92.88
2016	91.936
2017	92.029
2018	92.121
2019	92.211
2020	92.294
2021	92.372
2022	92.443
2023	92.506
2024	92.561
2025	92.61
2026	92.653
2027	92.69
2028	92.723
2029	92.755
2030	92.786
