The Subscribers report is where you can see how many people have subscribed to and unsubscribed from a given list, keyword, web form, or even synced from MailChimp. You can get a detailed breakdown and export the analytics for further review.  

Here is how to access your subscriber's report:

1. Log in and click Analytics in the left-hand side panel, toward the bottom.

2. Choose the Subscribers report. The subscribers report sits between the Messaging report and Billing stats reports. 

You can choose the time period for the report that you want to see. There are default time periods, or you can create a custom time period.

3. Once you select your time period, you will be able to see a summary chart of how many people have subscribed to and unsubscribed. Beneath the graph, you can see the same information for a given list, keyword, web form, or even synced from MailChimp.

4. You can also view a detailed breakdown by list, segments, keywords, web forms, and Mailchimp below the summary graph

You can also export this information in the form of a CSV file for further manipulation.