In light blue, we show the distribution of LCR sources by number of time bins with zero photons within the ROI used for their analysis. In magenta, we show the distribution of LCR sources according the number of time bins with fewer than 20 photons within the ROI used for their analysis. Darker shades of the lines refer to the 3 day cadence, while lighter dashed lines refer to the weekly cadence. The low-exposure time bins represent the 0.1% of the total time bins.