For planning production in the medium term, vehicle manufacturers need to forecast the demand for new motor vehicle sales. The following data are the numbers (in thousands) of Honda Ridgeline trucks manufactured by Honda during each quarter, starting from the first quarter of 2005 (when Ridgeline was introduced) until the third quarter of 2008. Assume that all Ridgelines produced in a quarter were sold in the same quarter.

YEAR	Q1	Q2	Q3	Q4
2005	11.5	19.2	17.4	12.7
2006	11.9	15.1	17.4	12.1
2007	10.6	19.1	13.9	11.5
2008	10.2	6.2	5.6

1. Compute the seasonal relative for each quarter using the centred moving average method.
2. Deseasonalize the data, fit an appropriate model to the deseasonalized data, extend the model four quarters, and reseasonalize these in order to forecast the sales of Ridgeline trucks in the fourth quarter of 2008, and first, second, and third quarters of 2009.