  We apply a new non-parametric Bayesian method for reconstructing the
evolution history of the equation-of-state $w$ of dark energy, based on
applying a correlated prior for $w(z)$, to a collection of cosmological data.
We combine the latest supernova (SNLS 3-year or Union2.1), cosmic microwave
background, redshift space distortion and the baryonic acoustic oscillation
measurements (including BOSS, WiggleZ and 6dF) and find that the cosmological
constant appears consistent with current data, but that a dynamical dark energy
model which evolves from $w<-1$ at $z\sim0.25$ to $w > -1$ at higher redshift
is mildly favored. Estimates of the Bayesian evidences show little preference
between the cosmological constant model and the dynamical model for a range of
correlated prior choices. Looking towards future data, we find that the best
fit models for current data could be well distinguished from the $\Lambda$CDM
model by observations such as Planck and Euclid-like surveys.
