Year	Percent
1990	83.636
1991	83.106
1992	82.611
1993	82.197
1994	81.742
1995	81.299
1996	81.063
1997	80.822
1998	80.591
1999	80.336
2000	79.848
2001	79.368
2002	78.882
2003	78.395
2004	77.907
2005	77.419
2006	77.011
2007	76.614
2008	76.227
2009	75.84
2010	75.447
2011	75.09
2012	74.74
2013	74.414
2014	74.143
2015	74.033
2016	74.14
2017	74.383
2018	74.644
2019	74.904
2020	75.15
2021	75.386
2022	75.606
2023	75.798
2024	75.952
2025	76.06
2026	76.131
2027	76.154
2028	76.142
2029	76.122
2030	76.112