Typical burn approx 2000kg
Typical distance approx 100nm
Therefore typical average burn approx 20kg/nm
As 20 is the average, you will understand that in the early part of the climb, FF will be about 8000kg/hr and speed about 250 kts, giving 32kg/nm.
At TOC, FF will be about 2500kg/hr and speed about 450kts, yielding 6kg/nm.
All these figures are from memory (10 years on 737 and 5 years on A321) so apologies for inaccuracies.