This article accompanies 'You've Got Maelstrom'

There's a clear divergence between the number of U.S. Postal Service employees and their productivity, according to a USPS Annual Report.

Two charts from that report show that as the number of employees dropped from 788,000 in 2000 to 585,000 in 2010, the total factor productivity rose from 9.9 in 200 to 20.4 in 2010.

Total factor productivity is a USPS measurement of the efficiency with which the postal service provides services. The TFP index is computed as the ratio of total workload to total resource usage.

Total workload is a comprehensive index of the services provided by the postal service while resource usage is a comprehensive index of the capital (plant and equipment), labor (employee work hours), and materials (transportation and other purchased goods and services) used in providing those services.

Increases in the TFP index over time, called TFP growth, represent efficiency improvements in providing those services.