Year	Percent
1990	83.931
1991	82.642
1992	81.567
1993	82.115
1994	81.893
1995	82.826
1996	80.484
1997	81.763
1998	82.357
1999	81.489
2000	80.471
2001	81.208
2002	80.645
2003	81.625
2004	79.78
2005	80.464
2006	79.876
2007	80.376
2008	79.35
2009	77.81
2010	77.072
2011	77.901
2012	77.066
2013	76.861
2014	76.669
2015	75.691
2016	73.981
2017	73.923
2018	73.854
2019	73.742
2020	73.571
2021	73.358
2022	73.092
2023	72.785
2024	72.459
2025	72.128
2026	71.807
2027	71.482
2028	71.157
2029	70.832
2030	70.51