A timely "Ask Me" from Ed Hines of Roswell, Georgia:
Where you cite your experience under your new-book section on your home page, should not "years" indicate possession? A missing apostrophe perhaps?
The full quote Ed's referring to says How to Not Write Bad "is based largely on my twenty years experience teaching writing at the University of Delaware." And he suggests it should say "twenty years' experience." My answer to his first question is "No," and because of that, my answer to his second question is, "Perhaps, but perhaps not." (A clue to the [philosophical] place from which Ed is coming is the way he deftly hyphenates "new-book.")
The apostrophe is without question the traditional way to go. But for some years there has been a move away from it for certain plural "possessives." Sir Ernest Gowers brings this up in his 1965 revision of H.W. Fowler's Modern English Usage. Discussing "Five years' imprisonment...