The phrase "almost wholly from" is correct and usable in written English.
It can be used to indicate that something is primarily derived or sourced from a particular origin, but not entirely so.
Example: "The report was almost wholly from secondary sources, which limited its originality."
Alternatives: "largely derived from" or "primarily sourced from".
My knowledge of Istanbul is not extensive and drawn almost wholly from PG Wodehouse.
In plain truth, our delight in the accomplishment of Col. Glenn has arisen almost wholly from the fact that he is an American.
But with government revenue coming almost wholly from oil, which is sold in dollars, it also meant less money in official coffers.
IN my own experience (I can with confidence only give that) I differ almost wholly from that of Mr. Joseph Le Conte, as expressed in NATURE (p. 452).
The fuss has seemed to come almost wholly from the omnivorous maw of the media, which had to wait for their meal instead of getting fed immediately.
Aulus Gellius (ca. 123 170 CE) is known almost wholly from his Noctes Atticae (Attic Nights), so called because it was begun during the nights of an Attic winter.
This love, free from instinct, free from all duties but those which love has freely assumed, almost wholly free from jealousy, and free without qualification from the need to be needed, is eminently spiritual.
The political wing of the progressive project in England has become almost wholly detached from the imaginative wing.
Almost wholly absent from the Northern Alliance leadership are members of Afghanistan's largest ethnic group, the Pashtuns.
It reportedly emphasizes not just Donald Trump's nationalism formalizing his call for a wall stretching across the Mexican border, and demanding that America "destroy ISIS but also a moral conservatism that was almost wholly absent from the Republican primaries.
His new business caters for the whims of a global elite, protected by their wealth from the pinch of the downturn and Britain's austerity era, their existences almost wholly disconnected from the lives of London's other residents.
