What index is used to measure the average prices paid by a typical​ family? An average of the prices of the goods and services purchased by a typical family is​ the: A. inflation rate index. B. consumer price index​ (CPI). C. producer price index​ (PPI). D. aggregate price level index. Suppose the​ economy's consumer price index​ (CPI) in 2008 was 188 and the CPI in 2009 was 199. The inflation rate over the period from​ 2008-2009 was equal to nothing​%. ​(Enter your response rounded to one decimal​ place.)