Year	Percent
1990	65.819
1991	66.792
1992	67.797
1993	68.366
1994	68.566
1995	68.466
1996	68.602
1997	68.614
1998	68.635
1999	68.63
2000	68.694
2001	68.574
2002	68.286
2003	67.856
2004	67.277
2005	67.032
2006	66.8
2007	66.556
2008	66.468
2009	66.962
2010	67.342
2011	68.681
2012	67.601
2013	68.775
2014	69.39
2015	69.933
2016	68.784
2017	68.935
2018	69.001
2019	68.95
2020	68.763
2021	68.451
2022	68.018
2023	67.486
2024	66.884
2025	66.239
2026	65.555
2027	64.834
2028	64.131
2029	63.526
2030	63.066