The days on which an instrument failed were recorded over a 12-month period such that day 1 ¼ Jan 1, day 32 ¼ Feb 1, etc.). Number of the day on which a fault occurred: 18 72 111 173 184 227 286 309...

The days on which an instrument failed were recorded over a 12-month period such

that day 1 ¼ Jan 1, day 32 ¼ Feb 1, etc.).

Number of the day on which a fault occurred: 18 72 111 173 184 227 286 309 356.