Jobs at the U.S. Postal Service have seen periodic culls over the past six decades, notably in the recessions of the 1970s and 1990s. But nothing on the scale or duration of what has happened since 1999. The number of postal workers has fallen from a peak of 909,000 in April 1999 to 601,300 last month. Employment numbers are back to where they were in 1965. Some analysts forecast they will fall to levels not seen since the mid-1940s, around 400,000, about the same number as UPS now employs and almost twice as many as FedEx.