Percentages (purple line) and binomial uncertainties (magenta region) of the planets that are singles as a function of planet radius (Sect. 3.2). These percentages are computed as a function of the mean of the planet radii in each consecutive bin comprising 100 singles in the FGK sample (panel a), 20 singles in the early-type M sample (panel b), and 15 singles in the late-type M sample (panel c). The sharp decline for the FGK sample occurs in the region of the multis overabundance at R ≈ 1.4–1.6 R_⊕.