"An estimated 854,000 people, nearly 1.5 times as many people as live in Washington, D.C., hold top-secret security clearances."
Which might place a rough estimate of tens to hundreds of thousands (depending on how many would be in the Military, work directly for the Govt, or work on other programmes)
Millions is probably overstating it though.
FTA:
"An estimated 854,000 people, nearly 1.5 times as many people as live in Washington, D.C., hold top-secret security clearances."
Which might place a rough estimate of tens to hundreds of thousands (depending on how many would be in the Military, work directly for the Govt, or work on other programmes)