Upper panel: protostellar disk substructure with or without a central cavity as a function of disk radius, mass, and bolometric temperature. Middle panel: fraction of disk with a central cavity versus the evolutionary stage traced by bolometric temperature. Bottom panel: fraction of disk with a central cavity versus the disk mass and radius. The bin size of eight disks was used to compute the fraction. The shaded region represents the 1σ uncertainty from counting statistics. All 24 protostellar disks are observed by ALMA Band 6 at a wavelength of 1.3 mm have a disk diameter greater than four times the resolution (θ_D/θ_res ≥ 4), with an inclination angle of less than 75°, and have substructures, and linear resolutions of less than 20 au.