How are monthly leaders calculated on c-sharpcorner

Question

Hi,

 

I have been active for last few days and my points are around  58 at the time I am posting this question. I happened to check the monthly leaders for May 2015 and was confused a bit. I can see that there are people who have earned say 15 points, but are included in the monthly leaders. I agree that there total points might be a factor in such calculation. So I wanted to know the algorithm based on which the monthly leaders are calculated here.

 

Thanks.