Subscribe rate

If i run an ad campaign with google adwords, how many of the people who clicked on my ad will subscribe?
Of course it depends on Content, but could you give a vague guess?
Like maybe 1 out of 1000? Or 10 out of 1000? Or more?

From my experience 1-1.5% tends to be the average rate. If you go over it, it means your targeting is working very well.