Year	Percent
1990	80.793
1991	80.88
1992	80.7
1993	80.605
1994	80.77
1995	80.511
1996	80.638
1997	80.659
1998	80.637
1999	80.663
2000	80.713
2001	80.848
2002	80.799
2003	80.693
2004	80.72
2005	80.782
2006	80.638
2007	80.671
2008	80.671
2009	80.819
2010	80.986
2011	81.005
2012	80.93
2013	80.824
2014	80.702
2015	80.546
2016	80.42
2017	80.303
2018	80.144
2019	79.947
2020	79.682
2021	79.399
2022	79.071
2023	78.701
2024	78.322
2025	77.939
2026	77.599
2027	77.273
2028	76.955
2029	76.647
2030	76.357