Euphemisms for "died" don't originate in the 20th century, or even in the modern era alone. The phrase "gave up the ghost" originates in the Bible, found 10 times in the King James Version. Given the tremendous impact this version had on the English language, it's no surprise that this phrase is still used today. In a similar way Paul uses the phrase "fallen asleep" to describe those who have died to the Thessalonian church in 1 Thess 4. Now you can argue that this is a theological word choice and not a euphemism, but nevertheless this is a re-naming of the unpleasant reality.
Pine River Boys, Co I, 7th Wisconsin
"We're... Christians, what read the Bible and foller what it says about lovin' your enemies and carin' for them what despitefully use you -- that is, after you've downed 'em good and hard."
-Si Klegg and His Pard Shorty