cosmology - At what speed does our universe expand?

Conceivably it expands with the speed of light. I do not know, but curious, if there is an answer. At what velocity, does our universe expand?

Answer

The rate of expansion of the universe (the fact that all objects are receding from each other and more so if they're farther away from each other) is given by the Hubble constant $H_0= 69.32 ± 0.80 (km/s)/Mpc$ ¹

Check out this plot from Wikipedia

On the y axis you have the velocity with which the object is receding from us and on the x axis the current distance in a common astrophysical unit called Megaparsec (parallax of one arc-second $1\text{pc} \approx 3.26$ light yrs).

Edit:

the discrepancy circled in blue is due to the galaxies having additional internal motions on top of their receding due to expansion. The galaxies measured there are (as the label says) part of the virgo cluster. The internal motion will induce a Doppler shift that will influence the overall redshift of the galaxy

^{1: According 20th Dec 2012 the Hubble constant, as measured by NASA's Wilkinson Microwave Anisotropy Probe (WMAP)}