Distribution of BB 95 (with respect to all BB) fraction against synchrotron peak frequency (i and ii) and radio variability Doppler factor (iii and iv). Pink crosses and solid markings refer to FSRQs (Q); blue dots and dotted markings refer to BLLs (B). Kendall’s τ correlation coefficient and significance are reported for FSRQs and BLLs. If a source has a BB95 fraction of zero, it is plotted in the top panels but not in the bottom ones. The running averages in the top row (shown as solid lines for FSRQs and dotted lines for BLLs) and the box plots in bottom row are both only calculated for at least ten nonzero values within each bin. In the top panels we show all data points, while in the bottom panels we zoom in on the boxes.