January 14, 1981
January 1, 1982
January 1, 1983
January 1, 1984
January 1, 1984
May 1, 1985
January 1, 1986
January 1, 1986
September 1, 1986
September 15, 1986
February 1, 1987
September 1, 1987
December 15, 1988
January 1, 1991
January 1, 1991
September 1, 1991
August 21, 1997
May 1, 2000
January 1, 2001
September 3, 2001
September 3, 2001
September 3, 2001
January 1, 2003
December 3, 2003
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September 12, 2005
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March 11, 2014
March 11, 2014
March 17, 2014