Answer:
20.8%
Explanation:
The number of the pieces of mail handled by the U.S postal service decreased from 212,000,000,000 to 168,000,000
Therefore the percentage decrease can be calculated as follows
= 212,000,000,000-168,000,000,000
= 44,000,000,000/212,000,000,000 × 100
= 0.2075 × 100
= 20.8 %
Hence the percentage decrease is 20.8%