Or you could look at it the other way, why in the world was +10% up from here the "right number" as to its value. Try to justify that first before questioning the contraction.
Also with 80%+ of all trading being algo, they are chasing each other to the bottom. The actual valuations might have been high anyway, but not to justify this.
We are likely going to hit one hell of a bounce once it does find the bottom.