United States. Bureau of Economic Analysis. "U.S. International Trade in Goods and Services: December 2017 : Highlights, Annual: 2017 Trade Gap is $566.0 Billion, BEA 18-06, CB 18-15, FT-900 (17-12)," Bureau of Economic Analysis (BEA) News Releases (February 6, 2018). https://fraser.stlouisfed.org/title/6148/item/602613/content/pdf/bea_newsreleases_20180206_release-highlights--annual, accessed on March 22, 2025.