Add Unsubscribe Rate to Email Campaigns dashboard

On the main Email Campaigns page (admin.php?page=fluentcrm-admin#/email/campaigns) that lists all campaigns and some metrics associated with them (Open Rate, Click Rate, etc.), it would be great to also display Unsubscribe Rate (or allow that as an option). I would like to be able to sort by Unsubscribe Rate - to see which campaigns have the highest rate of Unsubscribes (in order to improve future campaigns). Or if I could export this data into a spreadsheet, that would work, too. Thank you.