Report of of link clicks on a landing page

We set up a Marketo landing page containing a list of about 18 links to presentations from a seminar. The seminar registration was set up in a non-Marketo system, and the email sent out as a follow-up to the event was sent out through that non-Marketo system. It drives attendees to this page of presentation links so they can review the information post-event. Now the customer would like to know how many people clicked each of these 18 links. They don't need specific information on the IP the people are coming from, just a total number of clicks per link. What's the best way to get this data? The email has already been sent out (a few days ago), so triggered campaigns won't help.