Year	Percent
1990	68.205
1991	68.201
1992	68.211
1993	68.26
1994	68.127
1995	68.159
1996	68.163
1997	68.113
1998	68.076
1999	68.115
2000	68.055
2001	68.18
2002	68.353
2003	68.33
2004	68.314
2005	68.27
2006	68.167
2007	68.129
2008	68.08
2009	68.08
2010	68.095
2011	68.098
2012	68.085
2013	68.069
2014	68.054
2015	68.097
2016	68.062
2017	68.045
2018	68.037
2019	68.034
2020	68.032
2021	68.026
2022	68.02
2023	68.018
2024	68.019
2025	68.023
2026	68.024
2027	68.028
2028	68.035
2029	68.042
2030	68.045