Year	Percent
1990	81.022
1991	81.4
1992	81.499
1993	81.64
1994	81.522
1995	81.581
1996	81.702
1997	81.64
1998	81.541
1999	81.232
2000	81.078
2001	80.985
2002	80.714
2003	80.499
2004	80.472
2005	80.473
2006	80.31
2007	80.27
2008	80.156
2009	79.942
2010	79.395
2011	79.723
2012	79.662
2013	79.689
2014	79.699
2015	79.686
2016	79.591
2017	79.536
2018	79.468
2019	79.38
2020	79.273
2021	79.108
2022	78.914
2023	78.718
2024	78.554
2025	78.447
2026	78.354
2027	78.309
2028	78.307
2029	78.34
2030	78.399