It is possible to see the info about delivered emails, non-working emails, lists from those who opened the newsletter or clicked on a link in it (it's also possible to see at what time and how many times they did it), TOP links of the whole newsletter, countries, used e-mail programs (you can also see if they read it on mobile), who reported to spam, who unsubscribed etc. To see the aforementioned information, go to the "Campaigns" page (1) and click on the newsletter you want statistics for (2).
Delivery percentage shows what percent of the emails that were sent out reached the inboxes.
The opening percentage shows how many of those who got the newsletter opened it. Those are unique contacts who viewed the email - this is the effectiveness of the campaign. The number consists of all the addresses who have allowed to display the pictures (or have downloaded them) and/or who have clicked on at least one link.
The clicking percentage shows how many contacts clicked somewhere in the newsletter. The number consists of unique contacts that have clicked at least on one link. Behind this number you can see the real effectiveness of the campaign - the person has found the information what he/she was interested in and has found his/her way on your homepage (from there you can direct them wherever you want to with the help of buttons and/or different forms). Clicks are the most useful indicators. Most of those who clicked (if not all) have also displayed the pictures.
The last pane shows the number of people who unsubscribed from your newsletter.
If you want even more detailed statistics about your campaign, check the manual Exporting campaign reports.