Io, 114 bytes
Suffers from the existanceWhile you all are enjoying rounding built-ins in your language, Io doesn't have any of prepended 0
sthose convenient rounding built-ins. Is that allowed here? Edit: Fixed it anyway..
method(x,I :=((((x-31)/16)exp*100)round asString);I=if(I size<3,"0","").. I;I asMutable atInsertSeq(I size-2,"."))