proc power; TwoSampleFreq: How to write for a lower sided test ?

[Mgarret]

I’m trying to calculate minimum sample sizes for a A/B hypothesis test .   I hypothesizing a 10% decrease based on a historical benchmark of 5%.  How to you write the syntax for this.  The below is not correct.  Sides=L makes sense to me but in the GroupProportions = ( 0.05 -0.05) the -0.50 is is casuing an error. 

Any assistance will be greatly appreciated! 

proc power;
TwoSampleFreq
Test=Fisher
Alpha = 0.01
Sides = L
GroupProportions = ( 0.05 -0.05)
Power =.8
Npergroup =.;run;

[Rick_SAS]

 A proportion is a number 0 < p < 1. Try

groupproportions = (0.15 0.05)