"COVID-19 profoundly affected the U.S. Postal Service's mail delivery operations. Letters and total mail declined in 2020, but packages hit record levels.
According to USPS, its on-time performance was significantly affected when record package levels combined with employee absences due to COVID-19
-- especially in December 2020.
COVID-19 also drove up costs, with USPS reporting increased expenses for increased use of leave and personal protective equipment. Although 2020 revenues increased, the cost increases led to an additional $100 million in net losses for the postal service."