Here's my brief analysis on the PS4's sold-through numbers:
At the beginning of this year, Sony confirmed that the PS4 sold 18.5 million units up to January 4. Last month, Sony announced that they sold 20.2 million PS4's up to March 1. After digging up the NPD and Media Create numbers, here's the distribution of sales:
US = 534K
Japan = 210K
ROTW (i.e. Europe, Asia/Pacific, Middle East, etc.) = 956K
We know that for the first quarter of calendar 2015, the PS4 sold 870K in the US and 370K in Japan. If we assume the sales ratio between the US and ROTW remained the same, then the PS4 would have sold 1.558m ROTW, bringing Q1 CY2015 sales to ~2.8m, not including China. That brings cumulative worldwide sold-through numbers to 21.3m + whatever the PS4 sold in China.