If you allow me to insist, Jasper
Unless we have belly buttons in different places ...
Mine stays at circa 55 % of my total height.
Proportionally, a blade of 100 cms would correspond to a man 183 cms. tall.
Considering an average man of the period measuring 178 cms., its blade would ideally measure 98 cms.
We then would have that Jean Luc's blade, measuring 81 cms and considering it has been mae for a 'normal' man, would have been shortened by no more than 20 cms. as i first suggested.
So sorry for having switched the complicometer