Year	Percent
1990	67.172
1991	66.755
1992	66.368
1993	65.984
1994	65.622
1995	66.425
1996	67.349
1997	67.633
1998	66.362
1999	65.394
2000	65.828
2001	65.607
2002	65.521
2003	65.465
2004	65.37
2005	65.696
2006	64.787
2007	65.269
2008	65.29
2009	64.796
2010	64.455
2011	65.964
2012	65.172
2013	63.013
2014	62.459
2015	60.959
2016	60.658
2017	60.469
2018	60.278
2019	60.068
2020	59.83
2021	59.58
2022	59.308
2023	59.016
2024	58.708
2025	58.385
2026	58.068
2027	57.741
2028	57.406
2029	57.07
2030	56.736