Well, hard to tell ages exactly (just haphazardly added FW storage as space was needed), except for the newest - two 4 yr old SATA miniStacks (one at 10.4V and the other at 11.8V (unlike the others, this adapter has 4 rubber foot pads and its label has thinner font green print).
The others in question, best guess is those are about 6-8 years old - they're Mercury Elite (aluminum style) IDE enclosures which iirc came out to match the aluminum grille G5 circa 2004 - one is at 10.7V and the other 10.8V. And FWIW an "extra" black-print label 5-pin Jentec is outputting 11.95V.
Edit: Not enough data to be significant but looks like all the 10.xV outputs are green label JTA0202Y adapter models.
The others in question, best guess is those are about 6-8 years old - they're Mercury Elite (aluminum style) IDE enclosures which iirc came out to match the aluminum grille G5 circa 2004 - one is at 10.7V and the other 10.8V. And FWIW an "extra" black-print label 5-pin Jentec is outputting 11.95V.
Edit: Not enough data to be significant but looks like all the 10.xV outputs are green label JTA0202Y adapter models.