Year	Percent
1990	75.134
1991	75.091
1992	75.049
1993	75.154
1994	75.362
1995	75.635
1996	75.556
1997	75.632
1998	75.744
1999	75.887
2000	75.997
2001	75.922
2002	75.908
2003	75.833
2004	75.928
2005	75.982
2006	75.857
2007	75.769
2008	75.694
2009	75.667
2010	75.719
2011	75.385
2012	75.097
2013	74.224
2014	74.011
2015	73.901
2016	74.182
2017	74.084
2018	73.985
2019	73.882
2020	73.775
2021	73.662
2022	73.546
2023	73.43
2024	73.314
2025	73.201
2026	73.092
2027	72.986
2028	72.882
2029	72.783
2030	72.688