a#39;Excludes nonproducing operations for which separate figures are not available, as follows: 1939, 2 manganese ores mines and ... 13Excludes man-hours worked on inactive days, which are not available by department. ... 17Not computed since the number of proprietors and firm members performing manual labor exceeds one-third of the number ... In addition, includes Idaho, Arizona, Utah, Nevada, and Iashington for 1954, and Massachusetts, North Carolina, and Alabama for 1939.
|Title||:||United States Census of Mineral Industries: 1954|
|Author||:||United States. Bureau of the Census|