More than 12,200 value changes are recorded in Volume 4 of the 2012 Scott Standard Postage Stamp Catalogue. Leading the way are Japan, Korea and Malaysia. More than 4,100 value changes were made in Korea, and more than 3,500 in Japan.
In Malaysia, more than 1,800 value changes were made, with significant increases for modern flora and fauna topicals.
On the editorial side, more than 15 imperforate, imperforate between and double-impression errors have been added to various classic issues of Mexico, beginning with the Hidalgo Medallion set of 1884.