An interesting chart at Associate's Mind compares population growth and lawyer population growth in the U.S. from 1878 to today. The accompanying text explains:
While US population growth has been low (and dwindling) for decades, the amount of lawyers being produced has continued at a breakneck pace – particularly in the 1970s. The growth rate of the number of lawyers being produced only eased up after the original dot-com boom at the turn of the century.
An analysis of lawyer demographics is a hot topic today given speculation about how the market will react to the removal of Baby Boomer lawyers from the supply chain.