Year	Percent
1990	69.338
1991	69.066
1992	68.849
1993	68.552
1994	68.33
1995	68.041
1996	67.787
1997	67.547
1998	67.261
1999	66.973
2000	66.71
2001	66.525
2002	66.34
2003	66.154
2004	65.968
2005	65.781
2006	65.594
2007	65.406
2008	65.218
2009	65.029
2010	64.84
2011	64.651
2012	64.461
2013	64.27
2014	64.002
2015	63.733
2016	63.494
2017	63.359
2018	63.224
2019	63.089
2020	62.954
2021	62.819
2022	62.684
2023	62.549
2024	62.414
2025	62.279
2026	62.144
2027	62.009
2028	61.874
2029	61.739
2030	61.604