It is cumulative. Might as well include dmillos' other graph:
The next few weeks are going to be interesting as we see how PS5 behaves outside the holiday boost.
Wait, PS5 is launch-aligned in total only 280K ahead of PS4 anymore? OK, then the sales were very much frontloaded. Seeing the second graph shows this. After the first two weeks (second week is european lanch if I remember right) there is a sharp drop and not much of a christmas boost. Hmm. It really is interesting to see how PS5 goes on in the new year. I thought outside of japan the PS5 was strongly ahead of PS4, but it looks much closer in reality.