Damn the Sth Africans keep their movement figures close to their chest, so it took me about 20 minutes of Googling to dig them up. I guess they don't want to let out to the rest of the world how quiet their airspace is.
Sydney, even with a nighttime curfew in place, had for the month of March 2006, 24,438 total aircraft movements, whilst Joburg for the same month had 17,562 total aircraft movements (and that was their busiest month ever). Just to add to that, Bankstown, Sydney's second airport (mainly for light aircraft and the like) had a whopping 28,048 total movements for the month.
So sorry ATC Groove but I think you better rethink this whole idea of Joburg being ****loads busier than Sydney as it's not, in fact it is more on a par with Melbourne movement figures. Cheers.