he data itself is from 2011, much of it from protons colliding at 7 TeV (teraelectronvolts, you know) and producing those wonderful fountains of rare particles we all love to fail to understand. All told, it’s about half the total data collected by the CMS detector, and makes up about 2.5 inverse femtobarns. But who’s counting?
http://opendata.cern.ch/about/CMS