Year	Percent
1990	79.299
1991	79.111
1992	78.829
1993	78.485
1994	78.42
1995	78.563
1996	78.457
1997	78.615
1998	78.778
1999	78.799
2000	78.931
2001	79
2002	79.069
2003	79.074
2004	79.065
2005	78.966
2006	78.972
2007	78.86
2008	78.766
2009	78.688
2010	78.583
2011	78.433
2012	78.345
2013	78.307
2014	78.229
2015	78.182
2016	78.191
2017	78.165
2018	78.137
2019	78.106
2020	78.071
2021	78.032
2022	77.989
2023	77.945
2024	77.902
2025	77.864
2026	77.828
2027	77.796
2028	77.768
2029	77.741
2030	77.715