Proportionally (3,4)
I believe the answer is:
pro rata
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">proportionally</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for pro rata that I've seen before include "fairly divided" , "Proportionally" , "Proportional, according to the rate" , "maintaining correspondence" , "Proportionately based" .)