You could try breaking this down by using a People/Lead Performance Report. In the setup tab there's an option to define when a person was created (see screenshot below). You can select Custom if you want a custom date range.
Then group people by email address and check the Report tab.
*You can also group people by Acquisition Date or Acquisition Program if you want
Thank you both! I ran both of these and it turns out the report method that Tom suggested worked better for us.