Ionisation history as a function of the redshift, x_e(z), for the reionisation models considered. A few hundred samples from the MCMC distributions are shown in blue, while dashed black lines represent the 68th percentile of the distribution of x_e(z) for each redshift z. The solid and dashed red lines, respectively, correspond to the best-fit solutions and the frequentist confidence intervals determined by Δχ² < 1.