How many cases are there in the singular or plural?

How many cases are there in the singular or plural?

The form of predicate verb when percentage is the subject
When the phrase "fraction or percentage + of + noun" is used as the subject, whether the predicate form is singular or plural depends on their meaning
More than 70 percent of the earth's surface is covered by water.
More than 70 percent of the students in our class are league members.