For iOS and Android, we should remember that tablets are also counted there.
With that said, I think BlackBerry is making good progress and WP is not doing too bad either (for instance, no one had any figures on it last year, now there are 200,000).
With the hordes of Nokia WP's that are now on the market, I see a lot of the 4million strong current Nokia's converting to WP. Even worse if an even cheaper Nokia WP8 device is released soon. The 520 is selling like hot cakes from what I hear and so are the other lower range models.
First in line for loosing their position to WP in the table is iOS. Probably by the end of the year. Like BlackBerry, SA is one of Nokia WP's strongest markets.
P.S. Most of the 5million BB's are most likely BB7's.