Got some time at hand and sorted out some SAK's, an interesting observation I made was how the back of the can openers changed through the years.
These are the 5 different ones I found
A - late 50's early 60's
B - late 60's early 70's
C - late 70's early 80's
D - late 80's through the 90's
E - 2005 upwards
as with all things related dating SAK's these dates are not exact but if I group my SAK's according to year they correlate nicely with the exception of one SAK from the 80's
Rest is not idleness,
and to lie sometimes on the grass under trees on a summer's day,
listening to the murmur of the water, or watching the clouds float across the sky,
is by no means a waste of time