Year	Percent
1990	84.792
1991	84.739
1992	84.723
1993	84.719
1994	84.686
1995	84.593
1996	84.437
1997	84.224
1998	83.947
1999	83.599
2000	83.179
2001	82.531
2002	81.795
2003	81.029
2004	80.324
2005	79.733
2006	79.245
2007	78.869
2008	78.56
2009	78.244
2010	77.88
2011	77.665
2012	77.465
2013	77.247
2014	77.006
2015	76.728
2016	76.394
2017	76.065
2018	75.663
2019	75.217
2020	74.744
2021	74.247
2022	73.728
2023	73.182
2024	72.601
2025	71.983
2026	71.343
2027	70.685
2028	70.018
2029	69.355
2030	68.707