Is there a more general name for DiscountRate unit?

I have to create a Unit object representing Percent/Time. Examples: 4 %/year, 0.3 %/month, etc. The main use of this unit is for discount rates in NPV-like calculations. However the Unit is more general and I was wondering if there is a more general name for it.

As an aside note, I find it interesting that there is no tag for questions regarding units in this site.