Year	Percent
1990	73.726
1991	73.872
1992	73.657
1993	73.741
1994	73.396
1995	73.051
1996	72.704
1997	72.368
1998	72.022
1999	71.702
2000	71.391
2001	71.075
2002	70.771
2003	70.476
2004	70.189
2005	69.91
2006	69.632
2007	69.36
2008	69.114
2009	68.922
2010	68.797
2011	68.448
2012	68.153
2013	67.882
2014	67.6
2015	68.779
2016	69.539
2017	69.631
2018	69.706
2019	69.758
2020	69.784
2021	69.785
2022	69.762
2023	69.717
2024	69.655
2025	69.577
2026	69.481
2027	69.374
2028	69.259
2029	69.142
2030	69.029