Year	Percent
1990	73.541
1991	74.041
1992	73.776
1993	73.759
1994	74.152
1995	74.025
1996	74.136
1997	73.943
1998	73.857
1999	73.701
2000	73.063
2001	72.869
2002	72.643
2003	72.405
2004	72.163
2005	71.866
2006	71.608
2007	71.445
2008	71.31
2009	71.111
2010	70.923
2011	70.767
2012	70.602
2013	70.426
2014	70.34
2015	70.32
2016	70.271
2017	70.298
2018	70.338
2019	70.384
2020	70.431
2021	70.469
2022	70.506
2023	70.543
2024	70.576
2025	70.605
2026	70.619
2027	70.629
2028	70.632
2029	70.627
2030	70.611