A few weeks ago, Google began notifying webmasters who have deployed app deep linking about app deep linking issues and informing them how to fix it.
Now Google is sending webmasters stats on their impressions and click data via email as well. The emails currently have the subject line "your app in Google's search results: here are this week's stats on clicks and impressions."
The email then gives you a grid by day for the past week of impression and click data. Here is a screen shot from Andrea Pernici who posted this on Google+ and on his blog.
You can click on the image to enlarge.
Google is really pushing app deep linking!
Forum discussion at Google+.