From the data in Table 14-1 in the text, calculate the overall rate change of first-class postage as measured by the LCI for the following decades:
In Table 14.1

(a) The 1970s (1970-1979)
(b) The 1980s (1980-1989)
(c) The 1990s (1990-1999)

000000300380 1-3, 4 4 4 4 4 4 4 5 5 5 5 5 5 5 66 222333477 78 :9 000 15 000 000 33 000 00 000 000 00 33 00 00 00 00 00 030050005003000 3 100 3 3 3 6 2 2 2 2 2 250 06 08 08 08 20 20 20 0333555 012345678