cosmology - Is the effect of mass density on the expansion of the universe linear?

The average expansion rate for large scales parsec and above measured is $\approx 73\,{\rm km}\,{\rm s}^{-1}\,{\rm Mpc}^{-1}$. This expansion is calculated for average densities of space volume across space. However this expansion must vary significantly between voids and large mass concentrations.

My question in regards to this is if the effect on the expansion increases linearly with a linear decrease of mass density or it does not. Meaning for if there are other effects for this expansion even if minimal that are not accounted by mass.