Azimuthal velocity (V_ϕ) distribution as a function of Galactocentric distance based on the APOGEE sample (left) and the mass-weighted distribution orbit superposition (right). The mean trends in each panel are shown by the blue and red lines, respectively. Their comparison is shown in the bottom panel, where the solid black line represents the difference. The variation of the mean rotational velocity with azimuth in the orbit superposition reconstruction output is marked by the grey colour.