Year	Percent
1990	85.834
1991	85.815
1992	85.736
1993	85.536
1994	85.463
1995	85.305
1996	85.248
1997	85.211
1998	85.214
1999	85.17
2000	85.125
2001	85.344
2002	85.51
2003	85.614
2004	85.683
2005	85.719
2006	85.081
2007	84.418
2008	83.724
2009	82.995
2010	82.23
2011	81.499
2012	80.741
2013	80.512
2014	80.253
2015	79.983
2016	79.755
2017	79.662
2018	79.573
2019	79.5
2020	79.449
2021	79.417
2022	79.401
2023	79.395
2024	79.392
2025	79.386
2026	79.385
2027	79.382
2028	79.373
2029	79.355
2030	79.324