"Water, water, every where,Nor any drop to drink."
|English: Samuel Taylor Coleridge at age 42. Wikipedia)|
"waste, waste everywhere,
we never stop to think".
If the "average" building is notional (it must be) - it is everywhere, and at the same time nowhere.
What does this mean ? It's a simple and obvious idea, but it has implications...
On average they waste 30% so it fits. (Ok unlikely but to illustrate)