These stamps were issued without any denomination ... by design. They are not errors. They are still valid for postage at the rates indicated.

Dec 29, 1981	Nov 3, 1994	May 1, 1995
Denomination: 30c Scott# 907-908	Denomination: 38c Scott# 1536	Denomination when issued: 43c Scott# 1546
May 5, 1995
Denomination when issued: 43c Scott# 1551a
Sep 1, 2001
Denomination when issued: 47c Scott# 1918a-e
Jul 19, 2003	Oct 8, 2004	Nov 16, 2006
Denomination when issued: $1.25 Scott# 1991C Scott# 1991D	Denomination when issued: 49c Scott# 2063 Scott# 2064	Denomination when issued: 51c Scott# 2187 Scott# 2188 Scott# 2189-2193