United States. Bureau of Labor Statistics. "Employed and Unemployed Persons by Occupation, Not Seasonally Adjusted," in United States. Bureau of Labor Statistics. "January 2016," The Employment Situation (February 5, 2016) : 28-28. https://fraser.stlouisfed.org/title/144/item/522150/toc/516862 , accessed on April 23, 2024.