The U.S. report (updated quarterly) is available in several forms, including interactive, from links on the Bureau of Economic Analysis (BEA) NIPA ([https://www.bea.gov/index.htm]) page. Other countries report based on their own adopted system of National accounts which are frequently based on the U.S. NIPAs, the widely adopted United Nations System of National Accounts, or their own custom approach. The level of detail (granularity) accounted for internally, and reported publicly, varies widely across countries. Likewise, a nation's system of accounts, (analogous to a firm's Chart of accounts) are typically gradually revised and updated on their own individual schedule. The U.S. NIPAs are prepared by the staff of the Directorate for National Economic Accounts within the BEA. The source data largely originate from public sources, such as government surveys and administrative data, and they are supplemented by data from private sources, such as data from trade associations (BEA 2008: 1–6).