FB Logistics has been clearing containers from the port of Tema over the past seven years. Management is aware that the business has been facing seasonal fluctuations but there is no scientific basis for the determination of such variations that can be used to predict future revenue.
As a newly engaged Cost Accountant you have been provided with some past quarterly performance over a three-year period. Details of the performance are shown below:
                                    Year 1                 Year 2                    Year 3 

1st Quarter                   120                      180                        150
2nd Quarter                  140                      160                        200
3rd Quarter                   160                      185                        230
4th Quarter                   180                       210                       220
Required:
Using quarterly moving average, calculate the seasonal variation for the company.