Average hourly earnings in the U.S. retail trade industry (in current dollars and constant dollars) are shown in the table. Year Current dollars Constant dollars 1993 4.88 5.70 1998 5.94 5.39 2003 6.75 5.07 2005 7.13 5.00 2006 7.29 4.97 What are the slopes of the regression lines? What do they mean? (Use correct units.) What does this say about the long-term prospects of retail trade industry employees? Use the regression lines to estimate the difference in current dollar and constant dollar hourly earnings in the year 2008.