 Some collectors try to acquire a basic collection of the more common stamps from 1922 onwards , though that can be difficult now due to the quantity issued . Many collectors concentrate on one type of stamp , such as definitives or commemoratives , or even one issue , such as Gerl definitives . The First Day covers , especially commemoratives with full sets affixed , are popular though the older issues are harder to find because less than a million of the high value stamps were printed in the early years ( 1929 – 1940s ) for several issues , a far lower number than the 20 @-@ plus millions printed for most of the low values during the same period . 
