There's no definitive answer to this one but I've spent a lot of time analysing data from past years (specifically 2007 to 2013) to answer this question in 'purely mathematical' terms. I am going to share this data with you now, but remember, this is just going to be a mathematical perspective only.
Hopefully, this data will help you recognize:
a.) High scoring subjects (in each year)
b.) Percentage of familiar/non-familiar candidates that took up the subject and their passing ratio/numbers
c.) Co-relation between familiar and non-familiar students taking up a certain subject and their relevant success (in terms of scoring above 60% marks)
d.) The order of merit and the number of candidates allocated etc.
Note: I've highlighted the high-scoring subjects in Green followed by above-average scoring subjects in Blue (in the last 2 columns).
I hope this will prove to be beneficial for all and answers the high-scoring subject(s) debate once and for all!

P.S: Moderator, make this a sticky, if possible.

Here's the link to the post as I don't know how to paste images here:
https://www.facebook.com/CssOfficers...24353347602730