Year	Percent
1990	63.442
1991	63.22
1992	62.966
1993	62.675
1994	62.343
1995	61.978
1996	61.746
1997	61.517
1998	61.306
1999	61.119
2000	60.933
2001	60.717
2002	60.521
2003	60.348
2004	60.225
2005	60.5
2006	60.328
2007	60.193
2008	60.079
2009	60.042
2010	59.905
2011	59.652
2012	59.339
2013	58.938
2014	58.534
2015	58.421
2016	58.805
2017	58.645
2018	58.507
2019	58.347
2020	58.137
2021	57.846
2022	57.516
2023	57.16
2024	56.804
2025	56.46
2026	56.097
2027	55.748
2028	55.411
2029	55.082
2030	54.757