If I were a forecaster.... I would check out the new PROC X13 which replicates the X13 seasonal decomposition program of the US Census. Hint...It also provides utilities for automated ARIMA model selection for monthly and quarterly time series data. Read more at this link http://blogs.sas.com/content/subconsciousmusings/2015/09/10/sasets-14-1-adds-panel-data-models-and-model-comparison-utilities/