This is basic economics...you cannot only look at demand side when looking at quantity consumed.
A larger office has both larger demand of candidates and a smaller supply, all things constant. A smaller office has larger demand and smaller supply (presumably...if it is a smaller office because it is in a smaller country).
So, for every single office, the answer to your question depends on how many people are needed, and how many people apply.
In general, desireability of office plays a greater role here - in particular, offices that accept people from many backgrounds (read: English language).