Number of selected targets as function of reddening E(B−V), extinction A_V, the ratio of total-to-selective extinction R_V (=A_V/E(B−V)), and the fraction of molecular hydrogen f_H2for the target sample. The number of observed targets with reported values for each quantity are given at the top of each panel. The dark blue and light blue distributions correspond to the samples of observed and observed + foreseen targets. The vertical red lines indicate the value of the 5, 10, 25, 50, 75, 90, and 95 percentiles of each sample. The labels are located such that they trace the cumulative target distribution.