Create a case search to count all emails that were sent within a specific date range

 
1. Navigate to Lists > Search > Saved Searches > New > Case
2. Set the following fields as columns under Results tab > Columns subtab
  •Number
  •Messages Fields… > Email Sent
  •Messages Fields…> Author
  •Formula Numeric=Case when {messages.isemailed} = 'T' Then 1 Else 0 End
3. Set the Summary Type of the following columns:
  •Number=Group
  •Messages: Author=Group
  •Formula (Numeric)=Sum
4. Set the following filters under Criteria tab
  •Messages: Date=is within this year
  •Formula Numeric
  •Formula: Case when {messages.isemailed} = 'T' Then 1 Else 0 End
  •Formula Numeric=equal to > Value=1
5. Click Save & Run