Deconvolved widths (2R_jet) of CO (a), SO (b), and SiO (c) emission along the jet axis within 1500 au from protostars. Only flow detected above 10σ are measured. Non-axisymmetric structures that are well spatially resolved are discarded. Cyan lines indicate widths that are smaller that the transverse beam and consequently considered as inclusive upper limits. Green dashed lines correspond to straight lines with full opening angles of α = 3°, 8°, 12°, and 35° and initial width of 30, 50, 80, and 120 au outlining the collimation properties of the flow in different tracers.