Sister's doing a PhD here (or there rather, from your POV). Back of the envelope calculation, she'd be earning roughly 10% more than the minimum wage if you view a PhD as a 36 hours/week job (I wouldn't).

Pretty sure that that's close to the norm for PhD pay though.

(Sorry, no hard figures to compare, due to a feeling that I shouldn't discuss someone else's financial situation candidly online, even if details probably just a google away).