If you publish your presentation to a Connect server, it can
track each slide's viewership.
I have over 50 presentations published on a Connect server
(most, but not all, are public). Each of them has quizzes.
When I sign in to the Connect server, I can click Content,
and then click on a presentation name, and go to Reports. You can
look them up By Slide, to see how many times each slide has been
viewed.
Through experience, I have found that the first slide is
viewed the most, with a sharp decline over the next 2 or 3 slides,
and then it evens out through to the last slide.
If you would like to see examples, they are here:
http://vt.emerchantclub.com
(A few of those were published in Captivate but will be
re-done in Presenter over the next few weeks...)