Year	Percent
1990	92.994
1991	92.862
1992	92.729
1993	92.589
1994	92.436
1995	92.268
1996	92.088
1997	91.896
1998	91.695
1999	91.49
2000	91.283
2001	91.076
2002	91.144
2003	90.943
2004	91.323
2005	91.212
2006	91.101
2007	90.86
2008	91.156
2009	91.439
2010	91.039
2011	90.615
2012	90.138
2013	90.477
2014	90.548
2015	90.528
2016	90.249
2017	90.238
2018	90.227
2019	90.215
2020	90.201
2021	90.186
2022	90.169
2023	90.151
2024	90.13
2025	90.109
2026	90.087
2027	90.065
2028	90.043
2029	90.022
2030	90.003