The claim is backed up by real evidence. However it seems that a "major trip" means a really long one.
Some specific figures are found in this BBC History article by Jonathan Lamb, Mellon Professor of the Humanities at Vanderbilt University. In it he says:
Scurvy did not emerge as a problem for maritime explorers until vessels started penetrating the Indian and the Pacific Oceans.
So for most voyages such as "short" ones across the Atlantic scurvy would not be a major factor. But:
Vasco da Gama lost two thirds of his crew to the disease while making his way to India in 1499. In 1520 Magellan lost more than 80 per cent while crossing the Pacific. Two voyages made by Pedro de Quiros early in the 17th century resulted in huge mortality from [scurvy].
and
Commodore George Anson led a squadron into the Pacific in the 1740s to raid Spanish shipping. He lost all but one of his six ships, and two thirds of the crews he shipped (700 survived out of an original complement of 2000), most of them to scurvy.
So the figure is true for major voyages of exploration, but not necessarily for more run-of-the-mill voyages. This makes Wikipedia correct, but possibly in need of some clarification.