*When Oprah Winfrey said so long to her daytime audience last month, more than 16 million tuned in to witness history – which averages out to twice as many households than usual.

The Nielsen Co. reported today that the May 25 series finale of “The Oprah Winfrey Show” drew 16.4 million viewers, making it her most-watched episode in more than 18 years, reports the Associated Press.

The February 1993 airing of its “Why I Love Older Women” episode was seen by 17.3 million viewers.

Nielsen says the audience for the surprise farewell episode that aired May 23 drew 12.3 million viewers. The second part of that gala event attracted 13 million viewers when it aired May 24.

“The Oprah Winfrey Show” averaged 8.2 million viewers during May.