What's the number a console needs to sell not to be a failure?

[drake_tolu]

30,000,000.
12,000,000 in N.America (10,500,000 in USA)
9,000,000 in Europe.
6,000,000 in Japan.
3,000,000 in rest of world.

Es:
Nintendo 64 have sold good W.W, over 30,000,000.
But is failure in Europe and Japan.
GC have sold bad W.W... but in NA have sold very good!!!