You have the following information for the U.S. economy in 2011 and 2012

You have the following information for the U.S. economy in 2011 and 2012:

CPI-U
(1982-84=100)

2011 224.9
2012 229.6

Based on the above information, answer the following:

a. If someone says the "CPI-U for 2012 was 229.6", translate that into language that humans (in contrast to "econs") can understand. Be sure to briefly explain the cryptic "1982-84=100".

b. Using the above information, calculate the headline inflation rate in the U.S. from 2011 to 2012.