40c    -   Womans suffrage    - 1893
80c    -  Powered Flight         - 1903 (Richard Pearse)
$1.10 -  Splitting the Atom   - 1917 (Ernest Rutherford)
$1.20 -  Jet Boat                     - 1953 (Bill Hamilton)
$1.50 -  Mt Everest                - 1953 (Ed Hillary)
$1.80 -  Nuclear Free             - 1987

As I was helping an unsuccessful entrant in the design competition, I didn't have any involvement with this stamp apart from pleading with the post office to use, regardless of who won, an image of Rutherford as a young man. Had I been involved I would have suggested using 1917, the date he first did his work rather than 1919 the year he finally published his work. It is interesting to note the illustration concerns the nuclear model of the atom, not the splitting of the atom.