This is the 146th most frequent Hungarian word.
százaléka
"Százaléka" means "percentage of it" in English.
Here, 'százaléka' refers to the proportional part of 'bevétel' (revenue) being allocated to marketing expenses.
A cég bevételének huszonöt százaléka marketingre költődik.
Twenty-five percent of the company's revenue is spent on marketing.
Here, 'százaléka' is used to express a specific percentage fraction belonging to the plural noun 'diákok' (students).
A diákok kilencven százaléka befejezte a házi feladatot.
Ninety percent of the students completed the homework.
In this sentence, 'százaléka' specifies the fractional part of 'vízmolekulák' (water molecules) that consists of oxygen.