This chart breaks out the total pieces in 2015 as total volume was 154.2 billion pieces. First-Class Single Piece Mail was 20.6 billion. That being: Mail bear

This chart breaks out the total pieces in 2015 as total volume was 154.2 billion pieces. First-Class Single Piece Mail was 20.6 billion. That being: Mail bearing postage stamps — bill payments, personal correspondence, cards and letters, etc. https://about.usps.com/who-we-are/postal-facts/decade-of-facts-and-figures.htm https://about.usps.com/who-we-are/postal-facts/decade-of-fac...