Calculate difference between dates within the same column

I am trying to calculate the time between one inspection and the previous inspection based upon the inspection date. Is there a way to calculate a time difference when the two dates are in the same column? Below is a sample of the data that I have available. I'd like to be able to calculate something along the lines of:  

Facility Inspection # Inspection Date Time Lapsed (Calculated)
A 1 1/1/2018 Null, or 0, or N/A
A 2 3/5/2018 (Facility A's 2nd inspection date) - (Facility A's 1st inspection date)
A 3 5/12/2018 (Facility A's 3rd inspection date) - (Facility A's 2nd inspection date)
B 1 1/5/2018 Null, or 0, or N/A
B 2 7/2/2018 (Facility B's 2nd inspection date) - (Facility B's 1st inspection date)


(1) Answer