Relative fraction of XXL-S source types as a function of redshift. The black triangles represent all definite radio AGN (whether classified or not), the blue circles represent RL HERGs, the purple circles represent RQ HERGs, the red squares represent LERGs, the magenta triangles represent unclassified AGN (which potentially include LERGs and RL HERGs), the green diamonds represent SFGs, and the orange pentagons represent unclassified sources (which potentially include LERGs, RQ HERGs, and SFGs). The y-axis error bars for each population are Poissonian and are given by Eq. (15), calculated for each redshift bin. The errors along the it x-axis are the redshift bin widths.