Cumulative fraction of the total dust mass f_d,tot that has encountered a location where the dust density ρ_d exceeds the Roche density ρ_R as a function of the time t after the start of the strong-clumping phase t_d,clump. Simulations of the streaming instability in isolation (blue lines) as well as of the scenarios SIwhileVSI (orange lines) and SlafterVSI (green lines) with an initial dust-to-gas surface density ratio of 2% and a Stokes number of 0.1 are depicted. The cumulative fractions (solid lines) increase close to linearly (dashed lines) with time, with the increase being strongest in the scenario SIwhileVSI and weakest if only the streaming instability is taken into account.