This is the 988th most frequent Dutch word.
tachtig
Eighty.
The word 'tachtig' is used here as a quantifier to indicate an exact age.
Hij is precies tachtig jaar oud.
He is exactly eighty years old.
Here, 'tachtig' functions as a numerical adjective to describe the quantity of attendees.
Er waren tachtig mensen op het feest.
There were eighty people at the party.
In this context, 'tachtig' is used to denote a percentage, representing a part of a whole.