Year	Percent
1990	79.432
1991	80.271
1992	81.066
1993	81.79
1994	82.377
1995	82.381
1996	82.334
1997	82.235
1998	81.972
1999	81.633
2000	81.453
2001	81.494
2002	81.557
2003	81.694
2004	81.689
2005	81.587
2006	81.607
2007	81.668
2008	81.809
2009	81.975
2010	81.951
2011	81.893
2012	81.798
2013	81.828
2014	81.888
2015	81.979
2016	81.99
2017	81.996
2018	81.981
2019	81.902
2020	81.744
2021	81.502
2022	81.188
2023	80.826
2024	80.454
2025	80.092
2026	79.737
2027	79.394
2028	79.071
2029	78.776
2030	78.51