However, data from the NSF Survey of Doctorate Recipients suggest that most US-trained biomedical PhDs spend fewer than 5 years in postdoctoral positions. Some do remain in postdoc training a lot longer, though. There is some indication those who do the longest postdocs are the ones who go on to tenure-track academic research careers. For example, in the figure below, the age at first non-postdoctoral job (many of which are in industry) has been consistently a year or two lower than the age of obtaining the first tenure-track job. Note that the latest data in this graph (2002-2003) may be underreported due to delays in reporting that result in a lag time bias.
It's always nice to get a sense of the historical trend of things -- I wasn't aware that there was a time in the mid-eighties where it seemed it was difficult to get an academic position. One imagines that this is the sort of graph that you'd like to show an entering class of 1st year graduate students. Also, one imagines that all the lines have continued to trend up.