During administrative changes in the federal government, data sometimes is removed from federal sites.  In some cases the sites are moved, sometimes the sites have come down and the data is removed. 

This year, a number of sites have been removed or changed, we are working to keep our list of sites as up-to-date as possible.

Due to federal changes to govermental agency data policies, many websites and data sets have disappeared.  The group called Data Rescue is tracking locations of saved data that are now housed in other locations.  You may use this interactive grid to determine whether data has been retained and how to obtain that data.