Originally Posted by TMF
Yes, PC1 have explained that. But today's players faced better returners, slower surface.
Karlovic holds the record for most aces per match in 2007(better than Goran's best year in 1996), and he faced tougher condition/returners.
Not necessarily because as I mentioned he often doesn't last to the later rounds where he may often play a better returner.
Thing is that if players were better returners today relatively speaking it may stand to reason that the percentage of service breaks are higher. Yet I see at the top levels that servers seem to hold serve at a higher rate.
I have the stats for Sampras in the 1990's and he did lead the ATP most years in the 1990's if I recall correctly. It is an interesting discussion however.