Year	Percent
1990	84.386
1991	83.86
1992	83.364
1993	82.937
1994	82.477
1995	82.022
1996	81.804
1997	81.573
1998	81.34
1999	81.075
2000	80.582
2001	80.106
2002	79.623
2003	79.136
2004	78.647
2005	78.155
2006	77.752
2007	77.358
2008	76.975
2009	76.594
2010	76.212
2011	75.866
2012	75.53
2013	75.218
2014	74.956
2015	74.847
2016	74.973
2017	75.24
2018	75.522
2019	75.797
2020	76.049
2021	76.302
2022	76.531
2023	76.727
2024	76.874
2025	76.966
2026	77.03
2027	77.038
2028	77.007
2029	76.965
2030	76.932