How can I know how many emails were marked as spam?

Hi Jordan, 

Jumping into your question, if you want to see the overview of all of your communications and the number of emails that were marked as spam, you can see that by going to Dashboard > Performance. 

Click “More Analysis” to see the breakdown of marked as spam as a table or chart over the selected time period. 

Marked as spam means a person marked your email as Spam with their email service provider. All subsequent emails for them are marked “suppressed.”

Note: There’s no way to know in CIO how many of your emails went into the spam folder, just how many people marked your email as Spam. 

I hope this helps!