You don't need a hyphen when the modifier ends in -ly. From the Chicago Manual of Style:

Compounds formed by an adverb ending in ly plus an adjective or participle (such as largely irrelevant or smartly dressed) are not hyphenated either before or after a noun, since ambiguity is virtually impossible. (The ly ending with adverbs signals to the reader that the next word will be another modifier, not a noun.)

Also, if OP is interested in "correct" grammar, they should note that a hyphen shouldn't be used in the phrase "grammatically correct."

I just did the same Google searches and got the opposite results:

• Data is: 1,240,000,000
• Data are: 881,000,000

This is my favorite (clean, short) joke.

Knock knock.

(Who's there?)

Wooden shoe.

(Wooden shoe who?)

Wooden shoe like to know.