Thanks for the information. For some reason, 20 wpm seems to be the common answer you get from people, but most cannot attribute a source.
Your reply inspired me to do some more refined google searchs in a Canadian context. It looks like 20 wpm may have been the highest for Canadian hams (and going down since then), but higher for other services:http://jproc.ca/rrp/nro_ww2.html
Telegraphists ... regular course ... transmitting and receiving Morse at 22 WPM. http://strategis.ic.gc.ca/epic/internet/insmt-gst.nsf/vwapj/comments_e.pdf/
"Canadian Commercial Radio Operator’s license issued in 1948 when one was required to copy 20 wpm for 5 minutes without an error."http://www.ve3atc.spruce.ca
"I sweated on the 20 WPM code test and missed a few characters..."http://www.iosphere.net/~sullivan/Radio.htm
"Once you passed the 18 wpm tests you were excused daily morse practice."http://www.kwarc.org/extra1.html
"va3dg Go back to the system we had, i.e. an Amateur Class with 10WPM code and an Advanced Class with 15WPM code."
Other confirmation from V*'s appreciated.