0 0 LESS THAN 1 HOUR
1 1 1 TO LESS THAN 2 HOURS
2 2 2 TO LESS THAN 3 HOURS
3 3 3 TO LESS THAN 6 HOURS
4 4 6 TO LESS THAN 9 HOURS
5 5 9 TO LESS THAN 12 HOURS
6 6 12 TO LESS THAN 15 HOURS
7 7 15 TO LESS THAN 18 HOURS
8 8 18 TO LESS THAN 21 HOURS
9 9 21 TO LESS THAN 30 HOURS
15 15 MISSING VALUE
