Hi,
I specialize in creating custom-made tools for PDF files. I can create for you a stand-alone application that will do it, but the file must contain "real" text first, which means you'll need to run OCR on it. I'll also need to see some sample files, to understand where this number is coming from.
A little bit about me: I'm an Expert on both the Adobe and AcrobatAnswers forums and have a website dedicated to my custom-made tools for PDF files that you're welcome to check out (Google my handle-name to find it).
You're also welcome to check out my work history on this site and see some of the PDF-related projects I've worked on in the past.
Regards, Gilad (try67)