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| 1970 - 1973 | 1973 - 1983 | 1983 - 1994 | 1994 - 1996 | 1996 - 2003 | 2003 - 2005 | 2005 - 2006 | 2006 - Present |
| 1970 - 1973 |
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| 1973 - 1983 |
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| 1983 - 1994 |
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| 1994 - 1996 |
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| 1996 - 2003 |
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| 2003 - 2005 |
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| 2005 - 2006 |  |
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| 2006 - Present |  |
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