Made some very unofficial calculations based on data that I have.
FF's were based on NOMINAL weights cruise at FL370 for the
various acf types.
So, cruise thrust in percent of rated
B752 18,0%
B773 14,7%
MD80 21,4%
B744 14,9%
B763 15,0%
A319 19,6%
A340 16,8%
Cheers,
M