Good grammar, more or less
Fewer is the grammatically correct word.
When to use "less" or "fewer" is almost instinctive for writers with a propensity for correct grammar. The rest of us look it up. I frequently refer to one of my writing bibles, "The Careful Writer" by the late, great Theodore Bernstein, and double-checked the less vs. fewer entry before creating this post.
Thank you, Price Chopper, for doing it right.