Year	Percent
1990	64.767
1991	64.85
1992	64.636
1993	64.422
1994	64.207
1995	63.992
1996	63.776
1997	63.559
1998	63.342
1999	63.125
2000	62.907
2001	62.688
2002	62.469
2003	62.249
2004	62.029
2005	61.808
2006	61.587
2007	61.365
2008	61.143
2009	60.921
2010	60.697
2011	60.474
2012	60.25
2013	60.048
2014	59.7
2015	59.325
2016	59.008
2017	58.864
2018	58.72
2019	58.575
2020	58.431
2021	58.287
2022	58.142
2023	57.998
2024	57.854
2025	57.709
2026	57.565
2027	57.421
2028	57.276
2029	57.132
2030	56.988