How do I calculate the mean of a series across several periods?

  1. Select the Statistics analysis 
  2. Add “Mean” as a calculation.  
  3. Enter the data range you want used in the calculation  
  4. Repeat these steps for all the time periods you are interested in.  

For each calculation, you can untick the “Extrapolate” setting so that each line is drawn for the time period it is calculated on