Need help re: verifying a book's printing number

[wordsgood]

Hi folks. I'm more than a bit embarrassed to be asking this question, given how big of a book hound I am, but here goes anyway.

 

I sometimes have trouble identifying which printing a book is by reading the copyright/publishing info page. Sometimes I find it to be very clear, but sometime not. For example, the following is exactly as written (spaces and all) on the copyright page of a book I've recently acquired:

 

3 4 5 15 14 13 12

 

So does that mean I've got a 2nd, 3rd, 5th or 6th printing, or something else like an 11th, 12th, 15th, or 16th?

[chesilbeach]

Have a look at this Wiki page, which might (or might not!) help http://en.wikipedia.org/wiki/Printer's_key

[wordsgood]

I looked at the page you linked, cheslibeach, but alas am still lost. Hopefully someone else could help?