13 3 DURING THE PRECEDING 15 MINUTES
24 4 DURING THE PRECEDING 30 MINUTES
35 5 DURING THE PRECEDING 1 HOUR
46 6 DURING THE PRECEDING 2 HOURS
57 7 DURING THE PRECEDING 3 HOURS
68 8 DURING THE PRECEDING 6 HOURS
79 9 DURING A PERIOD OF MORE THAN 6 HOURS
810 10 UNDETERMINED
915 15 MISSING VALUE
10