The World Association for the Development of Philately (WADP) and the Universal Postal Union (UPU) jointly conceived and developed the WADP Numbering System - WNS, which was launched on 1 January 2002.

PY028.04

Country / Post Paraguay
Date of Issue 10 December 2004
Primary theme Energy (Hydro)
Subject Itaipu Binational Entity - 30th Anniversary of it's Creation
Width 45.0 mm
Height 35.0 mm
Denomination 4000 PYG
Number in set 2 (show set)
Layout/Format sheet of 25
Perforations 13.5 by 13.5
Stamp issuing authority Correo Paraguayo
Printer Fiscal Assets Department - Asunción