You can do this by creating a couple of calculated fields.
First, create a calculation similar to the following (in this example it's called 'previous'):
Then, using the above calculation, create a second similar to the following:
Place this on the view. Depending on how the table is set up, it may be necessary to change the way the calculation is being computed. To do this, right click on it and select Compute Using...
Hope this helps!