Numbers

Q. In expressing the statistical change in GDP figures over the course of multiple decades, would it be most correct to write “2000% increase,” “2,000% increase,” or “2,000 percent increase”? Our copyeditor favors the second option, but the use of the comma in that context just doesn’t sit right with me. Please advise.

A. All those styles are acceptable. In text, Chicago style spells out “percent” and favors a comma in integers over 999, but if your numbers appear in a table, “2000%” might look better.

[This answer relies on the 17th edition of CMOS (2017) unless otherwise noted.]