Year	Percent
1990	78.12
1991	78.113
1992	78.004
1993	77.727
1994	76.965
1995	76.632
1996	76.869
1997	77.154
1998	77.092
1999	77.117
2000	77.264
2001	77.482
2002	77.518
2003	78.033
2004	78.432
2005	80.216
2006	81.434
2007	80.746
2008	79.938
2009	78.956
2010	79.861
2011	80.337
2012	80.186
2013	79.734
2014	78.218
2015	78.723
2016	78.635
2017	79.046
2018	79.409
2019	79.656
2020	79.746
2021	79.728
2022	79.575
2023	79.319
2024	79.009
2025	78.681
2026	78.369
2027	78.037
2028	77.729
2029	77.504
2030	77.394
