For the United States, economist William T. Dickens found that full-employment unemployment rate varied a lot over time but equaled about 5.5 percent of the civilian labor force during the 2000s.
经济学家威廉·T·狄更斯（英语：William T. Dickens）发现美国的充分就业条件下的失业率随时代而波动，而在2000年代的美国，充分就业情形下的失业率大致为5.5%。