# Do I really need to put unit on the graphic?

I would like to add unit on this graphic:

As stated in many sources, I should place as much of the required information within the figure itself. Unit is a (very) important information so therefore I need to put it on the graphic. But where? I have a feeling that anywhere the unit is, it will make the graphic, erg, imperfect. And I think putting it in the caption won't harm the eye of readers. So do I really need to put it on the graphic?