Distributions of eccentricities of planetary orbits and fitted beta distributions. Black open bins: joint sample (1332 planets in single plus multiple stars); blue filled bins: single-star sample (1029 planets); red filled bins: multiple-star system sample (303 planets). The histograms are normalised to have a unit area. The three curve fittings (black for the joint sample, blue for single-star systems, and red for multiple-star systems) have beta distributions with different α and β parameters. See text for a description.