There is at least in our instance of Rally, (thing it came from git hub as it is a community app) a app that you can add to a blank page that will let you export cycle times to excel. You can run it at the parent level in rally with the "child projects" box checked in your heirarchy. that will give you data for all teams under that folder. You can pick the fields for the range, in your case it sounds like you just want "accepted" to "released". I choose to run Develop to Accepted because I want to see how long things are taking to get through dev, test, etc and be accepted. The app can give you two files, one with all the detailed data, and one with timestamps from when each item bounced from state to state etc. Once in excel you can do all kinds of stuff with the data from a reporting perspective. The app however factors in weekend days, coding issue, so we use a formula to extract the workdays and update a revised cycle time. We get velocity, throughput, cycle time etc all from this raw data, by team, org avg, etc.