We don’t need a formal study to tell us that email usage is increasing (do we?) … just look at our inboxes! But Cue did issue a 2012 email roundup revealing a bunch of interesting stats, including the increase volume of email in 2012.
In another look at the same report Michael Arrington of Techcrunch shares a stat that jives 100% with my own experience. If you are going to get a response to an email you sent, there is a 56% chance you will get it within an hour. If a response doesn’t come within 24 hours, you will probably never get one. 
So, what to do with all those aging emails in your inbox? You may as well delete them or archive them. No realistic person is still expecting a response anyway.
I’m intrigued and considering what you’re covering right here.