Is there any observational data available for evolution of Hubble rate? To give some context, read the dark energy FAQ by Sean Caroll here. He says: "If the universe is decelerating, the Hubble constant is decreasing. If the Hubble constant is increasing, the universe is accelerating. But there’s an intermediate regime in which the universe is accelerating but the Hubble constant is decreasing — and that’s exactly where we think we are." My question is: is there any observational data to prove that Hubble rate is decreasing, or is he just stating that the concordance model of cosmology predicts it to decrease with time? Looking at the Supernova data from Perlmutter et al, it seemed to me that the value of Hubble rate is actually increasing with time, but I may be wrong here!