The phrase "a serious proportion" is correct and usable in written English.
It can be used when discussing a significant or considerable amount or percentage of something in a formal or analytical context.
Example: "A serious proportion of the population is affected by this issue, highlighting the need for immediate action."
Alternatives: "a significant portion" or "a considerable amount".
David McDonald, co-director of the Municipal Services Project, said the government's own reports have portrayed a "crisis of serious proportions".
In the early 1980's it was recognized that asbestos litigation was going to cause a hemorrhage of serious proportions in the assets of asbestos-insulation manufacturers & their insurers.
When Hadrian left Rome in 134 for his final journey abroad, it was to resolve a problem of serious proportions in Judaea.
I'm an alcoholic in serious proportions and I need help physically and mentally.
After the war the nation found itself confronted with a crime wave of serious proportions.
That's big news, as it's tangible evidence that youth oriented online social networking is a market driver of serious proportions.
Production for its fourth and final season was interrupted by last year's writers strike, breaking the narrative rather neatly in half and providing the adrenaline rush of a midseason cliffhanger of serious proportions.
South Africa's health system is facing a shortage of trained health staff of serious proportions.
Thereby, acceptable fluorescence intensities (score: ++) were observed, although serious proportions of detached cells indicated a high number of dead cells (rating: 1 to 2) and the attached cells were strongly spindle-shaped/partially enlarged and showed vacuoles/lipids (rating: 3 to 5).
Secondary outcomes include the proportion of patients who experience an adverse event that could lead to a serious adverse event, proportion of patients who receive a significant intervention in response to an adverse event, proportion of patients who experience a successful sedation, and proportion of patients who experience a paradoxical reaction to sedation.
