I like WaPo as a source too, so it's claim of 56% might be in the ballpark.
But yeah, we might run in different circles. I spent my (1st!) career in corporate life. And even twenty years ago, drug testing was pretty much the norm among major large corps. Besides have been a permanent employee of several large American-based multinational corps, I spent much of my first career as an outside consultant/contractor. In virtually every instance there was pre-employment drug testing, and often it included outside consultants & contractors. And my experience here was with over a dozen corps.
As to government, my local governments all require drug-testing state/county/city.
Did you work for small or family businesses? If so, that may explain our different experiences.
Check-out the link below, in relation to large (Fortune 500) corps. It seems to be in concert with the WaPo article (62%):
Companies understand that implementing drug testing program significantly results in financial savings and makes workplace more productive and safer for others. Carrying out drug and alcohol tests throughout the nation has enabled Drug Testing Network to provide customized drug, alcohol and...
www.drugtestpanels.com