Some 4.4 million jobs have disappeared since the recession began in 2007.
The practice is spreading as the US unemployment rate hits 7.6 percent.
January's loss of 598,000 jobs hit factory workers and professional and business-services employees hardest.
Sales were better than expected this past Black Friday, but will it last till Christmas?
Loss of 20,000 jobs in April is the smallest decline this year.
In the first such loss in four years, 17,000 jobs were shed in January.