Year	Percent
1990	72.896
1991	73.289
1992	70.751
1993	69.706
1994	69.292
1995	68.595
1996	68.473
1997	68.651
1998	70.061
1999	69.701
2000	69.575
2001	70.08
2002	70.66
2003	69.869
2004	69.517
2005	69.252
2006	69.393
2007	69.156
2008	68.844
2009	67.478
2010	66.879
2011	66.818
2012	66.049
2013	64.941
2014	64.434
2015	64.163
2016	64.218
2017	63.769
2018	63.32
2019	62.869
2020	62.415
2021	61.955
2022	61.508
2023	61.072
2024	60.642
2025	60.216
2026	59.775
2027	59.344
2028	58.921
2029	58.501
2030	58.08