Consumption-per-person growth is not linear. It is also not smooth, there are step functions at (or rather around) certain group group sizes, where there's a dramatic change.

As to "below 1" (that is "shrinks") or above one ("grows"), it is heavily dependent on both macro-culture ("where are you", I do not expect these things to be the same in UK or Sweden, I suspect Canada is different again) and micro-culture ("office do", "theatre company", "IT gripe fest", ...)