Calculate Difference Between Same Field in Different Rows

[he204035]

If I have the following table using columns DATE and USAGE, is there a way to create a 3rd column to display the difference in the USAGE column from Day X to previous day?

DATE USAGE

Feb-28 Feb-29 Mar-01 Mar-02 Mar-03 Mar-04 Mar-05 Mar-06 Mar-07 Mar-08 Mar-09 Mar-10 Mar-11 Mar-12

17.68 gb 18.53 gb 19.66 gb 21.09 gb 22.04 gb 23.21 gb 24.20 gb 24.94 gb 25.64 gb 26.80 gb 27.79 gb 29.07 gb 30.09 gb 31.01 gb

[ITWhisperer]

Assuming these are numeric (not strings), you can use streamstats

| streamstats window=2 range(USAGE) as difference