A (significant?) uptick in below-guideline sentences in latest data run from USSC

The US Sentencing Commission has some notable new sentencing data now up on its website. The USSC's latest data report, which can be accessed here, is described this way:

Second Quarter FY09 Quarterly Sentencing Update:   An extensive set of tables and charts presenting fiscal year quarterly data on cases in which the offender was sentenced through the second quarter of fiscal year 2009 [which runs through March 31, 2009].  The report also provides an analysis of sentencing trends over five years for several key sentencing practices. (Published June 1, 2009)

The new data perhaps suggest a trend that I tentatively predicted in this post right after President Obama's election in which I suggested that the incoming administration might impact federal sentencing practice before we see any formal changes in policy.  Notably, though the new data run pre-dates the Obama Administration's announcement of a new attitude about crack sentencing policy and any other formal discussion of policy changes, this data run shows a (small but seemingly significant) uptick in below-guideline sentences imposed by judges.  Specifically, in the two quarters just before President Obama's election, judges decided on their own to impose a below-guideline sentence in roughly 13.8% of all cases.  In the two quarters since then, judges decided on their own to impose a below-guideline sentence in roughly 15.3% of all cases. 

Of course, it remains the case that most below-guideline sentences still result from prosecutors requesting a below-range sentence (this happens in roughly 25% of all cases). And, as has always been the reality in the federal sentencing system both before and since Booker, one can identify a number of large inter-circuit and inter-district variations in how many sentences fall within or outside calculated guideline ranges.