Year	Percent
1990	69.291
1991	69.889
1992	70.181
1993	70.204
1994	70.042
1995	69.857
1996	69.608
1997	69.361
1998	69.137
1999	68.957
2000	68.829
2001	68.815
2002	68.818
2003	68.829
2004	68.836
2005	68.836
2006	68.839
2007	68.829
2008	68.807
2009	68.774
2010	68.734
2011	68.689
2012	68.636
2013	68.423
2014	68.242
2015	67.909
2016	67.731
2017	67.738
2018	67.749
2019	67.771
2020	67.805
2021	67.845
2022	67.894
2023	67.95
2024	68.013
2025	68.084
2026	68.155
2027	68.231
2028	68.313
2029	68.403
2030	68.505