A guide for people making the decision for the first time.
Most people meet this once and never think about it again, which is exactly why it is worth reading up on.
Where to go from here
Nobody is required to explain this to you, which is half the problem. The figures move about, but the direction has been the same for three years.
What actually changed
Nobody is required to explain this to you, which is half the problem. The exceptions matter more than the rule, and there are three of them.
The short answer: check the date, then check the figure, then decide.