As of April 2008, the ELCA's Deaconess Community claimed 76 rostered women, "ranging in age from 27 to 91." It's down to 72 now, according to a more recent press release.
As for the LC-MS, a Concordia Seminary article from 2004 claims that there "are about 100" deaconesses serving. (Curiously, and perhaps tellingly, the article proposes deaconesses as a remedy for an apparent shortage of LC-MS clergy). The website of Concordia University, Chicago, gives these numbers, which we assume to be reasonably current:
None of this is decisive, both because it is vague and because it doesn't give data for comparison prior to the ordination of women by the LCA and ALC. All of which is further complicated by the different history of deaconesses in the various church bodies. But it does, in a preliminary way, suggest that, per capita, a denomination which does not ordain women does have significantly more consecrated female lay workers than one which does ordain women. So perhaps Morgan is onto something.