HHI 1000 or 0.1 industry, companies, percentage

anshultongia

if HHI is more than 1800, it is controled by few companies, if we remove the percentage, does it mean if HHI>0.18, industry is controled by few.

if HHI=0.15, does it mean we have SQRT(1/0.15 )=2 equal size companies?