Remember Don Imus' infamous remark about "nappy-headed ho's"? Or should that be "nappy-headed hos"?

The following publications used the apostrophe:
The Boston Globe
The Chicago Tribune
The Economist (UK)
The New York Daily News
The New Yorker
The St. Louis Post-Dispatch
The Village Voice (NY)
USA Today

The following publications omitted the apostrophe:
The Boston Herald
The Charlotte Observer
The Globe and Mail (Toronto)
The Guardian (UK)
The Miami Herald
The Telegraph (UK)
The Times (UK)
The Washington Post

The following publications were inconsistent:
The Nation (US)
The New York Post
The San Francisco Chronicle

Digression:
Dagens Nyheter, a Swedish newspaper, mistranslated the remark as "diaper-headed …"