Left panel: Number density of detections with S/N > 3.5 as a function of the survey tile depth in the r-band. Each point represents an individual tile. Side panel: Probability distribution of the number of detections per tile for the entire sample (gray histogram) and for the KiDS-N and KiDS-S stripes (blue and red lines, respectively). The corresponding values of the mean μ and RMS σ are reported in the legend. The absence of any significant correlation and the Gaussian shape of the number density distributions indicate the homogeneity of the survey clusters detection efficiency when a strict cutoff of r < 24 is applied in the selection of the input galaxy sample. A few outliers are visible, corresponding to tiles with problematic photometry (see their list in Table 1). We excluded from the analysis the tile marked with an “x” (see bottom-left corner).