The data in this release are based on data compiled by the U.S. Census Bureau (Census Bureau). These data are a complete enumeration of documentation collected by the U.S. Customs and Border Protection and are not subject to sampling error. Quality assurance procedures are performed at every stage of collection, processing and tabulation of the information. The Census Bureau quality assurance procedures include performing relational checks between the reported Customs value and quantity by Harmonized Tariff Schedule Chapter 99 numbers, which could lead to Chapter 99 unit prices that fall outside the bounds published in the Harmonized Tariff Schedule. Furthermore, the data are subject to non-sampling errors, and errors in low value estimation. For more information on these types of errors please see the Information on Goods and Services section of the FT900 U.S. International Trade in Goods and Services, page 26. The Census Bureau recommends that data users incorporate this information into their analyses, as non-sampling error could impact the conclusions drawn from the results.