The following is from a 14 March 2012 news item from the World Trade Organization.
After four years of negotiations and a year of work by WTO members on implementation measures and data collection, the WTO launched on 14 March 2012 a new publically available database on non-reciprocal preferential schemes.
This item is available in its entirety at:
http://www.wto.org/english/news_e/news12_e/rta_13mar12_e.htm