page number in pdf file using iTextSharp 5.0.2.0

I wanted to get the page number in each page of the pdf generated using iTextSharp 5.0.2.0.

right now part of the code is

e.FooterText = writer.CurrentPageNumber.ToString();

But when i do this , it is showing the page number but the problem is it is showing same page number in all the pages. like "1" in all the pages. how to get the page number for the pdf file using iTextSharp version 5.0.2.0 ??Any ideas ??