DU's official U.S. depository status dates back to 1909. However, many of the nearly 900,000 documents found in the collection date from the 18th century. Historically the Library had selected 70% of available depository materials, meaning that we have a rich legacy collection. Now, however, all of our receipts are in electronic format and we catalog 100% of items distributed by the Government Printing Office. Older materials can easily be requested from the Hampden Center.