Justin brings up the numbers cited by J. Arch Getty. Here 'tis again http://nuance.dhs.org/lbo-talk/0012/0436.html . The chart is easier to follow via http://www.egroups.com/message/marxist/1436 .
Conquest debated R.W. Davies on this in New Left Review issues, 219, 1996, pgs.143-44 and #225, 1997, pgs. 157-60. Michael Pugliese