The standard source for predictions and actual gross movie receipts is BoxOffice Magazine, which is accessible online at BoxOffice.com. BOXOFFICE, as the publication identified itself at the time, began in 1920 as an industry news publication. In 1937, it began reporting box office numbers using telegraph to transmit data quickly.
Another source for statistics is Box Office Mojo, a service from IMBD, which provides charts of sales data. Users are able to view actuals, predictions and studio estimates, in addition to gross over time. Box Office Mojo optionally organizes data by number of screens and production studios.
Another industry publication, Variety, also provides box office numbers and news. Variety articles cover both domestic and international sales.