One venerable source for benchmarks about the in-house legal community started years ago at PriceWaterhouseCoopers and made its way about six years back to what is now Thomson Reuters HildebrandtBakerRobbins. I have commented on results from that series, including particularly its compensation and personnel data (See my post of Nov. 6, 2007: incentive compensation; March 13, 2008: compensation data; March 16, 2008 #3: proportion of women in-house lawyers; April 24, 2009: compensation figures and Dec. 17, 2009: temps and contract lawyers.).
Other points I have extracted from the Hildebrandt benchmark survey vary widely (See my post of Dec. 5, 2007: data comparisons over 14 years; March 1, 2008: median total legal spending; Sept. 3, 2008: reporting lines of general counsel; April 13, 2009: matters and law firms retained; Dec. 3, 2009: cost control findings; Dec. 7, 2009: putative data on cost control efforts; Dec. 17, 2009: trivial cost control efforts; July 1, 2010: internal and external costs per hour; Oct. 20, 2010: 10% increase in participants; and Oct. 21, 2010: proclaimed drop in legal spending.).