Year	Percent
1990	76.805
1991	76.611
1992	76.425
1993	76.194
1994	75.901
1995	75.379
1996	75.192
1997	74.844
1998	74.335
1999	73.781
2000	73.307
2001	72.981
2002	72.745
2003	72.382
2004	72.049
2005	71.744
2006	71.712
2007	71.681
2008	71.643
2009	71.597
2010	71.541
2011	71.523
2012	71.609
2013	71.702
2014	71.746
2015	71.692
2016	71.645
2017	71.677
2018	71.695
2019	71.692
2020	71.666
2021	71.634
2022	71.584
2023	71.518
2024	71.441
2025	71.356
2026	71.278
2027	71.195
2028	71.113
2029	71.042
2030	70.989