Year	Percent
1990	78.285
1991	78.483
1992	78.488
1993	78.366
1994	78.313
1995	78.545
1996	78.711
1997	78.856
1998	79.013
1999	79.105
2000	79.053
2001	79.091
2002	78.95
2003	78.676
2004	78.359
2005	78.068
2006	77.874
2007	77.666
2008	77.43
2009	77.124
2010	76.719
2011	76.491
2012	76.18
2013	75.808
2014	75.417
2015	75.028
2016	74.794
2017	74.735
2018	74.685
2019	74.636
2020	74.583
2021	74.526
2022	74.465
2023	74.404
2024	74.346
2025	74.296
2026	74.248
2027	74.205
2028	74.165
2029	74.126
2030	74.086