Citing overcomplexity, increasing mobility of workers

[Guest]

In MGMAT CAT 1, Sentence Correction #23:

"Citing overcomplexity, increasing mobility of workers between companies, and poor financial planning, a recent study has estimated that less than half of eligible American workers contribute the maximum amount to their employer-offered retirement plans."

Is it correct to say 'less than half of American workers'? If American workers are countable, then shouldn't be fewer than half?

Thanks!

[Les]

LESS is used to quantify fractions (like half, one-third etc.). This may be the only instance that LESS is used with countable objects.

[dbernst]

This is a good question, and I can think of examples that definitely work with fewer. My best guess is that the GMAT will not use an ambiguous distinction between fewer and less as the sole determining factor between two answer choices. Instead, when the only difference in an answer choice is fewer v. less, the noun in question will be either clearly countable (fewer) or uncountable (less).

-dan