Year	Percent
1990	65.17
1991	65.098
1992	64.895
1993	64.566
1994	64.214
1995	63.863
1996	63.604
1997	63.351
1998	63.076
1999	62.877
2000	62.577
2001	62.593
2002	62.616
2003	62.456
2004	61.702
2005	61.548
2006	61.383
2007	61.213
2008	61.037
2009	60.852
2010	60.655
2011	60.443
2012	60.221
2013	59.987
2014	59.912
2015	59.873
2016	59.998
2017	59.895
2018	59.778
2019	59.653
2020	59.523
2021	59.385
2022	59.248
2023	59.113
2024	58.982
2025	58.858
2026	58.732
2027	58.617
2028	58.516
2029	58.437
2030	58.384