| 2025-01-01 | 2.54 | DT | |
| 2024-05-01 | 2.363 | DT | |
| 2022-10-01 | 2.208 | DT | |
| 2020-10-01 | 2.064 | DT | |
| 2019-05-01 | 1.938 | DT | |
| 2018-05-01 | 1.82 | DT | |
| 2016-08-01 | 1.717 | DT | |
| 2015-05-01 | 1.625 | DT | |
| 2014-05-01 | 1.538 | DT | |
| 2012-07-01 | 1.451 | DT | |
| 2011-05-01 | 1.375 | DT | |
| 2010-07-01 | 1.31 | DT | |
| 2009-08-01 | 1.253 | DT | |
| 2008-07-01 | 1.211 | DT | |
| 2007-07-01 | 1.153 | DT | |
| 2006-07-01 | 1.112 | DT | |
| 2005-09-01 | 1.078 | DT | |
| 2004-07-01 | 1.049 | DT | |
| 2003-07-01 | 1.015 | DT | |
| 2002-07-01 | 0.974 | DT | |
| 2001-07-01 | 0.94 | DT | |
| 2000-05-01 | 0.899 | DT | |
| 1999-08-19 | 0.87 | DT | |
| 1999-05-01 | 0.86 | DT | |
| 1998-08-20 | 0.831 | DT | |
| 1997-11-07 | 0.819 | DT | |
| 1997-07-20 | 0.79 | DT | |
| 1996-09-09 | 0.78 | DT | |
| 1996-05-01 | 0.77 | DT | |
| 1995-05-01 | 0.741 | DT | |
| 1994-08-01 | 0.707 | DT | |
| 1993-08-01 | 0.697 | DT | |
| 1993-05-01 | 0.687 | DT | |
| 1992-08-01 | 0.649 | DT | |
| 1992-05-01 | 0.639 | DT | |
| 1991-08-01 | 0.601 | DT | |
| 1990-01-01 | 0.591 | DT | |
| 1989-08-01 | 0.543 | DT | |
| 1988-04-01 | 0.529 | DT | |
| 1987-11-01 | 0.505 | DT | |
| 1986-07-01 | 0.481 | DT | |
| 1983-01-01 | 0.457 | DT | |
| 1982-02-01 | 0.409 | DT | |
| 1981-04-01 | 0.311 | DT | |
| 1980-05-01 | 0.263 | DT | |
| 1980-02-01 | 0.23896 | DT | |
| 1979-05-01 | 0.232 | DT | |
| 1978-05-01 | 0.21425 | DT | |
| 1977-02-01 | 0.193 | DT | |
| 1975-06-01 | 0.145 | DT | |
| 1974-01-01 | 0.13 | DT | |
| 1971-05-01 | 0.104 | DT | |
| 1968-05-01 | 0.084 | DT | |
| 1966-01-01 | 0.084 | DT | |
| 1961-04-01 | 0.076 | DT | |