title: % of New Email Addresses Per Month
body: <p>how to create a result that has % of new customer emails in a given month</p>
  
  <p>email addresses = email
  date = created_at</p>
  
  <p>note: created_at is in unix code</p>
  
  <p>pseudo code could be
  1 - count of distinct emails between date x and date y (denominator)
  2 - count of distinct emails between date x and date y where email is not between date a and date x (numerator)</p>
  
  <p>help! thx!</p>