Year	Percent
1990	77.684
1991	77.934
1992	78.275
1993	78.231
1994	78.142
1995	78.117
1996	77.929
1997	77.827
1998	78.057
1999	77.882
2000	77.839
2001	77.83
2002	77.724
2003	77.575
2004	77.102
2005	76.596
2006	76.343
2007	76.135
2008	76.496
2009	76.471
2010	76.129
2011	76.741
2012	76.23
2013	75.753
2014	76.282
2015	75.359
2016	75.165
2017	75.127
2018	75.097
2019	75.066
2020	75.031
2021	74.979
2022	74.927
2023	74.871
2024	74.808
2025	74.735
2026	74.64
2027	74.538
2028	74.433
2029	74.328
2030	74.226