X Per long-term light curve with JEM-X in the 3 − 10 keV and 10 − 20 keV energy bands as blue stars, and ISGRI in the 20 − 40 keV, 40 − 60 keV, 60 − 100 keV, and 100 − 200 keV energy bands. The average JEM-X count rate is shown as a dotted blue line. The average ISGRI count rate is shown as a dash-dotted black line. The value of 0 cts/s is shown as a solid black line. The NuSTAR 3 − 79 keV count rates are shown as a red and green triangles and have been normalized by a factor of 0.5.