Some projects actually state that number.... 100 lab years done in 2 or whatever.

If 20,000 CPU years are needed to do XYZ and the scientists are only having access to say 25 cores, then it would take them 800 days none stop, 24/7. Well, WCG chews through 110,000 CPU years per year at present mean power and rising. Add to that the fact that the grid is constantly upgraded... someone replaces a a P4 or a duo with an I7-860, where the researchers could not afford to do that to keep pace at their limited budgets so things are kind of exponentially getting faster. HFCC does an average of over 50 CPU years daily at present, middle of college holidays resume phase, so expect them to finish the second set of 3 targets in under 9 months where for the first 3 targets were anticipated to take two years (done in 15 months). That's allot of gain.