Interpretation of %p.a. notation Does anyone know the meaning of the notation x%p.a.?

I'm reading a text on seigniorage, and the authors have used that notation to state the usual empirical limit to the seigniorage revenues just before the inflation rates effects outweigh the money growth effect.
It's a proportional rate - 5% p.a. means 5% per annum, i.e. 5% per year