Year	Percent
1990	67.534
1991	67.588
1992	67.626
1993	67.705
1994	67.6
1995	67.673
1996	67.713
1997	67.804
1998	67.822
1999	67.854
2000	67.914
2001	67.965
2002	68.015
2003	68.045
2004	68.067
2005	66.575
2006	65.068
2007	63.503
2008	61.883
2009	60.219
2010	58.17
2011	58.463
2012	55.583
2013	56.742
2014	55.764
2015	57.677
2016	56.056
2017	55.919
2018	55.808
2019	55.724
2020	55.663
2021	55.618
2022	55.589
2023	55.567
2024	55.538
2025	55.494
2026	55.433
2027	55.357
2028	55.264
2029	55.154
2030	55.03