Question to AntPlus.PedalPowerBalance

Powerbalance for cycling usually is given by left-percent to right-percent.

There is a class Toybox.AntPlus.PowerBalance.
The sample in Toybox says:

var pedalPowerPercent = PedalPowerBalance.pedalPowerPercent;

Since I have no dual powermeter on my bike to test, I kindly ask you: what is the result of pedalPowerPercent?
It is Number. Is it percentage left/right? So, perfect balance gives 100? Unbalanced gives + or - percentage?

Thank you!