obsid   target                  start time      int time    inst    ccd     grat    drop rate(%)
-----------------------------------------------------------------------------------------------------------
16357	Crab                	30:00480.651		 9.6	ACIS-S	S1		NONE	20.9
16358	Crab                	109:84766.403		 9.6	ACIS-S	S1		NONE	20.1
16359	Crab                	228:15679.040		 9.6	ACIS-S	S1		NONE	19.6
16258	Crab                	310:15029.600		 9.6	ACIS-S	S1		NONE	18.5