The vertical axis of the "Sentencing Table" provides for categories based on criminal history points. The following is a picture of each category (I, II, III, etc.) and how many points each category is attributed.
For example, a defendant who has 3 criminal history points will find herself in criminal history category II. Determining how many criminal history points a defendant has is governed by Chapter Four of the USSG.
§4A1.1 of the USSG provides the following:
Various exceptions apply which may result in certain prior sentences not being counted. It is important to consult with an experienced federal criminal lawyer who will make sure your criminal history is properly calculated.