I couldn't find it either but in addition to "Code Complete" this data is also shown in a chart in "The Software Project Survival Guide", also by Steve McConnel

I couldn't find it either but in addition to "Code Complete" this data is also shown in a chart in "The Software Project Survival Guide", also by Steve McConnell (p29). The attribution is "Researchers have found" but Boehm and Papaccio are listed in the references.