Your choice : Stamps by type -> Cover issued by WWF

Year of stamps of Cover issued by WWF	Quantity
CoverWWF:Cover issued by WWF (Year unknown)	10
CoverWWF:Cover issued by WWF (From 1972 till 1975)	2
CoverWWF:Cover issued by WWF (From 1976 till 1979)	2
CoverWWF:Cover issued by WWF (From 1980 till 1983)	1
CoverWWF:Cover issued by WWF (From 1988 till 1991)	8
CoverWWF:Cover issued by WWF (From 1992 till 1995)	11
CoverWWF:Cover issued by WWF (From 1996 till 1999)	6
CoverWWF:Cover issued by WWF (From 2000 till 2003)	4