Year	Percent
1990	77.311
1991	77.507
1992	77.358
1993	77.214
1994	77.078
1995	76.951
1996	76.807
1997	76.669
1998	76.541
1999	76.428
2000	76.334
2001	76.282
2002	76.24
2003	76.203
2004	76.166
2005	76.125
2006	76.11
2007	76.086
2008	76.061
2009	76.04
2010	76.029
2011	76.027
2012	76.029
2013	75.812
2014	75.52
2015	75.178
2016	74.879
2017	74.912
2018	74.944
2019	74.98
2020	75.022
2021	75.066
2022	75.113
2023	75.164
2024	75.221
2025	75.282
2026	75.346
2027	75.414
2028	75.482
2029	75.549
2030	75.614