Fractional expressions - subject or not?

[grammarnix]

Is it true that fractional expressions are not usually the subject of the sentence (i.e. football players, cane field, students, student body) and it is the subject (whether its plural or not) that actually determines whether the verb is plural or single....??

Eg. Two-fifths of the football players were lost in the protest.

[thomas]

Expressions such as two fifths of the players and 20 percent of the participants are often used as subjects of sentences. Although grammar texts disagree on how to treat such subjects, most speakers and most ESL texts treat these subjects as though they are plurals. Yes, most people would say:

Two-fifths of the football players were lost in the protest.