Formal uncertainty of the orbits measured by σ_a/_a, where a stands for the semi-major axis of the osculating orbit, and σ_a shows its standard deviation. Top: First 50 000 numbered asteroids. Bottom: complete solution of 157 000 orbits. The vertical line at a = 3.15 au corresponds to a period of 66 months, which is the longest arc in the data. The vertical scale is adapted to each set.