The core of the APP document collection is based on published collections of presidential documents.  Except for recent presidents, these collections omitted many documents such as proclamations, vetoes and orders. So, users should note that prior to 1945, the total number of documents in the APP collection in a specific category is almost certainly smaller than the actual total number. So, based simply on document frequencies, our collection overstates the activity level of the post-FDR presidency compared to earlier years.