was excision of those provisions of the law establishing the Guidelines as mandatory. In the aftermath of Booker and other Supreme Court cases, such as Blakely v. Washington (2004), Guidelines are now considered advisory only. Federal judges (state judges are not affected by the Guidelines) must calculate the guidelines and consider them when determining a sentence but are not required to issue sentences within the guidelines. Those sentences are still, however, subject to appellate review. The frequency in which sentences are imposed that exceed the range stated in the Guidelines has doubled in the years since the Booker decision. Guidelines basics The Guidelines determine sentences based primarily on two factors: the conduct associated with the offense (the offense conduct, which produces the offense level) the defendant's criminal history (the criminal history category) The Sentencing Table in the Guidelines Manual shows the relationship between these two factors; for each pairing of offense level and criminal history category, the Table specifies a sentencing range, in months, within which the court may sentence a defendant. For example, for a defendant convicted on an offense with a total offense level of 22 and a criminal history category of I, the Guidelines recommend a sentence of 41–51 months. If, however, a person with an extensive criminal history (Category VI) committed the same offense in the same manner in the same modern timeline and not during the older guideline periods, the Guidelines would recommend a sentence of 84–105 months. Offense level There are 43 offense levels. The offense level of a defendant is determined by looking up the offense in Chapter 2 and applying any applicable adjustments. The originally proposed sentencing guidelines had 360 levels, and there are proposals to substantially reduce the current number of offense levels. Criminal history There are six criminal history categories. Each category is associated with a range of criminal history points. Thus, for example, a defendant with 0 or 1 criminal history points would be in Criminal History Category I, while a defendant with 13 or more criminal history points would be in Criminal History Category VI. The criminal history points are calculated by adding 3 points for each prior sentence of imprisonment exceeding one year and one month; adding 2 points for each prior sentence of imprisonment of at least sixty days but not more than 13 months; adding 1 point for each prior sentence of less than sixty