Nasal width/length ratio is:
Nasal index is the ratio of nasal width to nasal height multiplied by 100. 
The nose has been classified into three major groups based on the nasal parameters:

Leptorrhine or fine nose (nasal index of 69.9 or less)
Mesorrhine or medium (nasal index of 70.0 – 84.9)
Platyrrhine or broad nose (nasal index of 85.0 or more)
62.50%
70%
65%
66%