100%
'100%' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for all that I've seen before include "in toto" , "nothing more" , "Entire" , "The works" , "The whole amount" .)
(Other definitions for pure that I've seen before include "Free of extraneous elements of any kind" , "Innocent; unsullied" , "free of contaminants" , "Virtuous" , "Innocent, uncontaminated" .)