The 10th U.S. Census in 1880 took over 10 years to complete. It became obvious that the growth in population would require a new means to calculate the census faster and easier. One U.S. Census Bureau agent, Herman Hollerith, became intrigued by the thought of automating the tallying process.

Hollerith conceptualized using punched holes in cards to record facts for census-taking. This concept was not unique, as Charles Babbage's "analytical engine" used punched cards to guide its calculations. Hollerith's machine tallied items by causing an electrical current to trigger simple clock-like counting devices.

The preceding was taken from:
Biles, George E., Alfred A. Bolton, Bernadette M. DiRe. "Herman Hollerith: Inventor, Manager, Entrepreneur -- A Centennial Remembrance. Journal of Management, 1989, vol 15, No. 4, 603-615.