39 CFR 3055.22: Periodicals.

(a) For each product within the Periodicals class, report the on-time service performance (as a percentage rounded to one decimal place).

(b) For each product within the Periodicals class that does not meet its service goal during the reporting period, report the point impact data for the top ten root causes of on-time service performance failures, at the National level, during the previous fiscal year. “Point impact data” means the number of percentage points by which on-time performance decreased due to a specific root cause of failure. Identification and a description of all potential root causes of failure assigned during the previous fiscal year and any changes to the Postal Service's methodology for calculating point impact data shall be included.