The phrase "a tiny fraction are" is correct and usable in written English.
It can be used when referring to a small percentage of a larger group or quantity, typically in statistical or descriptive contexts.
Example: "In the survey, a tiny fraction are aware of the new policy changes."
Alternatives: "a small percentage are" or "a minuscule portion are".
A tiny fraction are surviving to return upstream, aided by fish ladders.
(Despite what some reports have suggested, only a tiny fraction are only available now — a thousand two hundred and sixty-nine as of Friday afternoon).
Euronesians (people of mixed European and Polynesian ancestry) account for most of the rest of the population, and a tiny fraction are of wholly European heritage.
While humans are more varied than most, there are literally billions of people alive right now, let alone the past and future of our species and yet a tiny fraction are over 7 feet tall.
Many crimes are never reported — this is true of rape in civilian life as well as in the military — but among those that are, only a tiny fraction are dealt with in any meaningful way.
"Only a tiny fraction aren't using it, despite the lies of your reporter," retorted the mayor's aide.
Of the total workforce, only a tiny fraction is now employed in the primary sector (agriculture, mining, and lumbering).
Meanwhile, native-born New Yorkers blamed all Irish Catholics (about a quarter of the city) for the riot, even though only a tiny fraction was involved.
The campaign organisation 38 Degrees said Walkers' production of 11 million crisp packets a day meant its new recycling scheme had only led to a tiny fraction being recycled since its launch.
Statistics from the European Commission show that 185,000 people applied for asylum for the first time across the EU in the first three months of this year, but only a tiny fraction were in Britain.
The body which polices it said a "tiny fraction" were flouting the law.
