It's possible it's even older than this, but the earliest mention I can find of that quote has it being attributed to a Reverend T. Garrott Benjamin, Jr. in 1987: http://books.google.com/books?id=2bMDAAAAMBAJ&pg=PA16
... And possibly only one profession is phonier. Advertising design, in persuading people to buy things they don’t need, with money they don’t have, in order to impress others who don’t care, is probably the phoniest field in existence today.
Interesting chain of "inspiration" :)