Year	Percent
1990	76.603
1991	76.357
1992	76.108
1993	75.859
1994	75.614
1995	75.374
1996	75.066
1997	74.939
1998	74.811
1999	74.685
2000	74.563
2001	74.469
2002	74.381
2003	74.283
2004	74.157
2005	73.996
2006	73.845
2007	73.627
2008	73.347
2009	73.017
2010	72.748
2011	72.288
2012	71.708
2013	71.265
2014	70.835
2015	70.363
2016	69.98
2017	69.888
2018	69.812
2019	69.754
2020	69.713
2021	69.696
2022	69.7
2023	69.721
2024	69.758
2025	69.806
2026	69.86
2027	69.925
2028	69.997
2029	70.071
2030	70.142