"reduced number" is correct and can be used in written English.
For example, "Due to the current health crisis, there has been a reduced number of customers in the restaurant."
Reduced number of specimens for material characterization.
RAGE blockade reduced number of Nestin-positive NSCs that co-expressed RAGE 3 days after SCI.
Thannickal, T. C. et al. Reduced number of hypocretin neurons in human narcolepsy.
However, quercetin treated cells showed a significantly reduced number of ASC specks (Fig. 4A,B).
An aperture rectification algorithm is then applied to generate a significantly reduced number of deliverable apertures.
Reduced number of substantial interventions.
Group III (c) showing reduced number of positively stained cell.
These questionnaires contain a significantly reduced number of survey questions.
They found a substantially reduced number of OPCs in the brain exposed to methotrexate.
"Change needs to show up in grades, reduced number of suspensions and dropout rates," he said.
Consistently, electron microscopy revealed reduced number of docked vesicles.
