How are DX contacts based on?

Hi, VK4SHG

Here, just a quick question on the way DX contacts are calculated on leaderboards? At the time of writing I have 1 Australian contact and 22 overseas contacts but on the leaderboard it shows only only 10 DX ? I did get a number of Indonesian special operations stations but, even that doesn’t add up to only 10 DX?

Regards,

Scott Garrett