How much of the vote gets transferred

The election process treats all candidates the same by giving them a "keep value".

Allows candidates to keep the portion of the vote they need to be elected
and
Allows any extra or surplus votes to be distributed proportionately amongst the other candidates, according to voters" preferences.

Here's how the keep value works:

If the quota or number of votes needed to gain election is 100, and a candidate only receives 100 votes, they keep all 100 of those votes. So they have a keep value of 1 (100%).

But if the candidate received 200 votes, they still only need 100 of those votes to be elected. So the other 100 can be transferred to the voters' second choice. In this case the candidate's keep value would be 0.5 (50%), because they only needed to keep 50% of the votes they received to be elected.

You can also tell by the keep value how popular each candidate is with voters. The most popular candidates will have the lowest keep value - because they received so many votes, they only needed to keep a small proportion to gain election.