Fraction of stars with discs as a function of time. The solid black line shows the results for ρ₁₀₀ and the dashed black line for ρ₅₀ . The grey shaded areas indicate the standard deviation of the simulations. Observed disc fractions in star-forming regions of different ages are shown for comparison. The orange line shows the mean of the observations, calculated using a moving bin spanning 10 observation points.