General GNSO Processes & Background:
...
Summary of Privacy & Proxy Prevalence Findings from Prior Studies
List of ICANN-Accredited Registrars (as of May 2014): https://www.icann.org/registrar-reports/accredited-list.html
Other Background Documents:
...
WHOIS Review Team Final Report May 2012.pdf
EWG Initial Report June 2013.pdfEWG Status Update Report Nov 2013.pdfPP Survey Summary of Results 14 March 2014
EWG Final Report June 2014 (note in particular Section VII (including specific recommendations related to Privacy & Proxy Services) and Annex H)
Whois Studies (selected reports):
...
WHOIS Registrant Identification Study - Project Summary Report NPL's Initial Report on June 2013
WHOIS Privacy & Proxy Abuse Sept 2013Abuse Study Final Report March 2014