The phrase "a modest fraction of" is correct and usable in written English.
It can be used to describe a small or limited portion of something in a more understated manner.
Example: "The study revealed that a modest fraction of the population was affected by the new policy."
Alternatives: "a small percentage of" or "a slight portion of".
The Ahdab oil field represents only a modest fraction of Iraq's oil wealth — the field is expected to produce 90,000 barrels of oil a day.
The cost of redoing these piers would be about $70 million, a modest fraction of the $1.2 billion provided earlier by Washington to help revive the city.
Why would you be willing to work so hard and take so much risk for only a modest fraction of ownership?
A10 Rumsfeld Details His Plan Defense Secretary Donald H. Rumsfeld described his vision of military transformation as one that might not even challenge current weapons programs or involve more than a "modest fraction" of the Pentagon's forces.
Compared with the cost of packaging, marketing and other ingredients, cocoa sometimes represents a modest fraction of the overall cost of a candy bar, said Susan Smith, a spokeswoman for the United States Chocolate Manufacturers Association.
Not only do they constitute a modest fraction of the land area, which itself is less than one-third of Earth's surface, but they are often obscured by clouds.
A modest fraction (approximately 20%) of primary amines of PAMAM can be modified while maintaining the siRNA delivery efficiency of unmodified PAMAM, but higher degrees of amine neutralization reduced the gene silencing efficiency of PAMAM/siRNA delivery vectors.
Thus, differences in genetic sequences can be the primary determinant only for a modest fraction (typically 10%20%%) of TF binding differences between these mammalian genomes.
Imagine, if you will, if you needed to make use of a modest fraction - say 2% - of those patents to develop a new pharmaceutical product.
The employees own virtually 100 percent of the company (there are a few advisers who are also shareholders and I myself own only a fairly modest fraction of it).
This indicates that most HPV infections are subclinical and only a small fraction of HR-HPV infections produce early epithelial lesions, and a more modest fraction of those lesions will develop into cancer.
