"The congressional notion was that the Postal Service was making lots of money selling its products and services, and so it might be a good idea to put those profits into pre-funding future retiree health care benefits for the next 75 years and do so in a decade. No one else, public or private, does this – but it would put the Postal Service that much more ahead of the game in terms of future liabilities. And so, in 2006, Congress mandated that the USPS do so, at a price tag of about $5.5 billion a year. " (http://www.cnbc.com/id/45049636/Fixing_the_US_Postal_Service039s_Finances).