Typical additional latency for CGN?

Have there been studies on how much latency CGN adds to a typical internet user? I'd also be interested in anecdotes. I've seen theoretical predictions but by now we should have measurements from early-world deployments. Thanks, Tom -- Speaking at MacTech Conference 2012. http://mactech.com/conference http://EverythingSysadmin.com -- my blog http://www.TomOnTime.com -- my videos