Fraction of double-peaked LAEs plotted against the logarithmic Lyα luminosity. The unbiased sample U has been divided into four luminosity bins with the same number of objects (51 or 52). The fraction of double-peaks has been derived in each bin for both UDP_I and UDP_R. The results are positioned at the median Lyα luminosity of each bin. The fractions of inclusive double-peaks are represented in black colour. The X_DP R of the restrictive sample are in orange. The horizontal black line at the top of the figure shows the size of each Lyα luminosity bin.