Here a nanny's hourly wage is usually around $9-$10/hr, DOE. I was a nanny and made $10/hr for one kid, with 5 years nanny experience. When they had a second I got a raise.
A friend was a nanny for twins in our area and she started at $12/hr.
I suppose you could pay up to $14/hr but I've never seen anyone around here ask for that! Even though it tends to be lower here than most other places, I think our general wages are lower too. I couldn't afford a nanny at $10/hr and both DH and I work.