Click on the following links. Please note these will open in a new window.

The Sentencing Project
The Sentencing Project is a national non-profit organization engaged in research and advocacy in criminal justice issues

U.S. Sentencing Commission: 2014 Annual Report
This report descriptive statistics of the federal sentencing guidelines and provides district, circuit, and national sentencing data.
The Commission has a Retroactivity Report that is also useful:

The State of Sentencing 2014: Developments in Policy and Practice
This Sentencing Project report examines new developments in sentencing policy and practice throughout the United States.