The data are available under the ODC Open Database License (ODbL)(http://opendatacommons.org/licenses/odbl/1.0/) (summary available here: http://www.opendatacommons.org/licenses/odbl/1-0/summary/): you are free to share and modify the data so long as you attribute any public use of the database, or works produced from the database; keep the resulting data-sets open; and offer your shared or adapted version of the data-set under the same ODbL license.
