Largely this goes back to how we assign levels for the given year, and therefore as the minister presents the levels for the coming year, the global number each fall. Within that there are also numbers for the various categories, and so it's always a balancing act, quite frankly, among the various categories to try to get the right number.
Essentially, that's how it comes about. There's no scientific formula to it. It's trying to balance the needs of the country and the emphasis the government wants to place on a particular category.