Year	Percent
1990	81.335
1991	81.479
1992	81.347
1993	81.409
1994	81.51
1995	81.63
1996	81.761
1997	81.951
1998	81.868
1999	81.754
2000	81.61
2001	81.834
2002	82.054
2003	82.264
2004	82.455
2005	82.624
2006	82.792
2007	82.14
2008	82.004
2009	81.86
2010	82.045
2011	82.105
2012	80.014
2013	79.917
2014	81.811
2015	79.745
2016	79.85
2017	79.854
2018	79.863
2019	79.877
2020	79.894
2021	79.927
2022	79.967
2023	80.01
2024	80.055
2025	80.1
2026	80.152
2027	80.207
2028	80.258
2029	80.298
2030	80.323