Year	Percent
1990	68.683
1991	68.303
1992	67.95
1993	67.509
1994	67.006
1995	66.489
1996	66.001
1997	65.552
1998	65.161
1999	64.735
2000	64.285
2001	63.945
2002	63.579
2003	63.248
2004	63.796
2005	64.364
2006	64.921
2007	65.505
2008	66.997
2009	65.112
2010	63.274
2011	62.787
2012	63.306
2013	63.39
2014	63.656
2015	64.974
2016	65.169
2017	65.24
2018	65.303
2019	65.352
2020	65.382
2021	65.374
2022	65.346
2023	65.298
2024	65.228
2025	65.136
2026	65.009
2027	64.86
2028	64.696
2029	64.53
2030	64.37