1880 US census had taken 7 years to complete since all processing had been
done by hand from journal sheets. The increasing population suggested that by
the 1890 census, data processing would take longer than the 10 years before
the next census —so a competition was held to find a better method. It was
won by a Census Department employee, Herman Hollerith, who went on to found
the Tabulating Machine Company, later to become IBM. He used Babbage's idea
of using the punched cards from the textile industry for the data storage.
His machines used mechanical relays (and solenoids) to increment mechanical
counters. This method was used in the 1890 census and the completed result
(62,622,250 people) released in just 6 weeks! This approach allowed much more
in-depth analysis of the data and so, despite being more efficient, the 1890
census cost about double (actually 198%) that of the 1880 census. The
inspiration for this invention was Hollerith's observation of railroad
conductors during a trip in the western US; they encoded a crude description
of the passenger (tall, bald, male) in the way they punched the ticket.