hex-rey hourly traffic in percent of capacity week 30 in 2021

/data/traffic/plot/plot-hr -n hex-rey -d 2021--30 -t traffic -f png  >/data/traffic/html/imgs/hr.traffic.hex-rey.2021--30.png
Illegal division by zero at /data/traffic/plot/plot-hr line 97.
Plot failed, ret = 255