Rural Electric Magazine, Dec. 2016, by Frank K. Gallant.
http://remagazine.coop/flashbacks-rural-electrification-cartogram-numbers/

"....In 1940, just four and a half years after Roosevelt signed Executive Order No. 7037, 25 percent of American farms had been electrified. Among the bigger farm states, Indiana (37 percent), Ohio (42 percent), and Washington (57 percent) were electrifying fastest. Ten years later, 90 percent had been electrified nationally. REA was proving to be one of the most successful government infrastructure-building programs in U.S. history."