EROS-2 (B_E − R_E, R_E) color − magnitude diagram of the ratio of the number of variable stars to the total number of stars. The color − magnitude diagram is divided into a matrix of 250 × 250 bins, each bin being 0.014 × 0.028 mag wide. The ratio is plotted according to a color-scale shown on the right of the figure. Only bins with at least ten stars and a ratio above 0.1 are plotted. Color version of the figures in this paper are available in the online version.