Year	Percent
1990	73.919
1991	73.599
1992	72.95
1993	72.61
1994	71.995
1995	71.837
1996	71.617
1997	71.308
1998	71.195
1999	70.918
2000	70.556
2001	72.039
2002	69.8
2003	69.744
2004	68.794
2005	67.548
2006	67.542
2007	67.025
2008	66.147
2009	65.89
2010	66.421
2011	66.741
2012	66.043
2013	66.46
2014	66.763
2015	66.828
2016	66.884
2017	66.619
2018	66.37
2019	66.111
2020	65.828
2021	65.526
2022	65.202
2023	64.872
2024	64.562
2025	64.288
2026	64.058
2027	63.86
2028	63.686
2029	63.524
2030	63.37