Subject is U.S. salesperson statistics, probably BLS data.  I want to
show growth in the subset of salespeople who sell from business to
business, as opposed to all others.  (All others mainly include retail
salespersons behind a counter, plus salespeople who sell direct to
consumers like Avon or car dealers).  The subset I'm looking for would
include people who sell for technology companies, industrial
companies, parts of financial services, and so forth.  If that's not
clear, please come back to me for clarification.
Timeframe: I'm looking for big picture trends going a good ways back:
ideally, say, 1920s to now, datapoints every 10 years or so.  I don't
need a huge amount of detail, just to make sure the definitions are
clear and a few datapoints that show a trend.