Using the data in the file Macro2010, develop an autoregressive model for imports. First, use the data for the period 1970, first quarter, through 2000, fourth quarter, to forecast for the quarters in years 2001-2003. Then use the data from 1970, first quarter, through 2007, fourth quarter, to forecast the quarters in the years 2008 and 2009. Discuss the differences in the accuracy of the forecasts compared to the actual results and indicate reasons for these differences.