Year	Percent
1990	77.529
1991	77.796
1992	77.817
1993	77.996
1994	78.288
1995	78.377
1996	78.142
1997	77.872
1998	77.739
1999	77.511
2000	77.105
2001	76.494
2002	76.002
2003	75.607
2004	75.151
2005	75.247
2006	75.252
2007	75.347
2008	75.516
2009	75.444
2010	75.846
2011	75.912
2012	76.08
2013	76.306
2014	76.803
2015	77.043
2016	77.227
2017	77.276
2018	77.199
2019	76.977
2020	76.604
2021	75.992
2022	75.246
2023	74.416
2024	73.576
2025	72.775
2026	71.936
2027	71.14
2028	70.444
2029	69.923
2030	69.616