The time series chart below depicts monthly interest rates on 30-year fixed-rate mortgages in the United States from 1977to 2009 (blue line).The chart also includesrates on 15-year fixed-rate mortgages from late 1991 to 2009 (red line).What conclusion(s) can you draw from the times series chart of these mortgage rates? Specifically, what has been happening to mortgages rates in general, and how does the behavior of the 30-year rates compare to the behavior of the 15-year rates?

20.00 Time Series Chart of montly interest rates 18.00 16.00 14.00 12.00 10.00 -30-year Rate 8.00 -15-year Rate 6.00 4.00