Quality of the orbit determination measured by the post-fit uncertainty of the semi-major axis for the whole sample of objects contained in Gaia DR2 after the nominal 5 yr (red points) and 10 yr (blue points) of mission. Black points represent the current situation (initial orbits taken from AstDyS). The orange points are the post-fit uncertainties using only 22 months of Gaia observations available for the Gaia DR2.