ISS recently released its 2012 Burn Rate Caps as part of its 2012 U.S. Proxy Voting Summary Guidelines (December 19, 2011), p. 44, available at http://www.issgovernance.com/files/2012USSummaryGuidelines.pdf
The presentation below includes these burn rate caps as well as a chart looking at how the caps have changed from 2009 through 2012.
Update: After posting this, I discovered that with its December 1, 2011 quarterly download, ISS Research is now using a 3-year observation period for stock price volatility in both the Shareholder Value Transfer (SVT) and burn rate tests. The 200-day annualized volatility is no longer being used.