Pretty much every year. The US has included a one cent stamp in all of their definitive stamp sets. You will need to consult the catalogs to find the specific types and how many years they were actually issued, though they are always available.
1932
How much is 15 cent martin Luther king stamp worth
15 cents
That is Scott number US 2418 It has a value of 1.30 mint and minimal 15 cent used.
Aproximately New .80 Used .40
The 8 cent silver .20 cents (mint and used) The 15 cent gold .60 cents mint and .55 used.
That would be Scott number US 1581 or 1811. Both versions can be purchased for 15 cents mint and 15 cents in used condition.
This stamp is Scott number 1798. It can be purchased for about 20 cents used and 35 cents in mint condition.
This stamp is still easy to find.You should be able to buy a mint or a nice used copy for20 cents.
This stamp is Scott's number 231. A very fine used copy is worth about 10-15 cents; mint is about $8.00.
Scott #2226 can be purchased used or mint for about 15 cents.
This stamp came out on March 15 (his birthday) in 1967.
Scott number 1581 It can be purchased mint or used for .15 cents. Most dealers won't purchase a single stamp.