Mass ratio (q) distribution for the iDR5 SB2 sample. Blue: whole sample of 148 q estimates; orange: only systems with a relative uncertainty on q lower than 30 %; green: only systems with a relative uncertainty on q lower than 20 %; red: only systems with a relative uncertainty on q lower than 20 %. The number of systems for each cut is indicated in the legend box. The four histograms are superimposed; thus, for instance, the visible green part of the bars only shows the system with a relative uncertainty on q between 10 % and 20 %.