(Top left) Sky area covered by various maps along with the position of all the 24 μm sources (915, dot symbols) and the sample of YSCs (648, open circles). Coordinates are for the J2000 epoch. (Top right) Histogram of the number of clusters N as a function of the galactocentric distance R_G for Mid-IR sources (white) and YSCs (grey). (Bottom left & right panels) Profiles of the number density of clusters per unit area in kpc² in linear and log scale, respectively, as a function of galactocentric distance for the same samples. See text for details on the disk deprojection model.