With the addition of email client reports for all our customers, we took a step back and analyzed 12 months of data covering more than half a billion opens. The result - a birds eye view of email client popularity and usage trends over time.

To the best of our knowledge, this is the largest study on email client popularity ever undertaken. We'll be updating these figures each quarter or so to give you insight into the latest in email client usage. To learn more about how we measured usage and why some results may be skewed, check out the fine print.