The phrase "a gradual decrease in the number" is correct and usable in written English.
It can be used when discussing trends, statistics, or changes over time, particularly in contexts such as research, reports, or analyses.
Example: "The study revealed a gradual decrease in the number of participants over the course of the year."
Alternatives: "a steady decline in the number" or "a slow reduction in the number."
As the chyme moves from the duodenum to the ileum, there is a gradual decrease in the number of segmenting contractions.
We've pulled them out below to make them easier to see: The broad trend over the decade is a gradual decrease in the number of child murder victims – though the figures have been largely stable in recent years, at around 50 victims in total each year.
It entails a gradual decrease in the number of dislocations and a rearrangement of the remaining ones into orderly arrays.
In an age where theaters are seeing a gradual decrease in the number of attendees, hedging their bets through non-traditional licensing deals, video-on-demand sales, and international ticket sales is becoming increasingly important.
Overall, there is a gradual decrease in the number of oligonucleotides that differentiate a species pair, with corresponding decrease in sequence length (Figure 4C and 4D).
There was a gradual decrease in the number of CFU-GM and BFU-E for samples removed at the end of primary drying and during secondary drying; however, there were no differences in the number of CFU-GEMM (∼82%).
There was, however, evidence of a gradual decrease in the numbers of labelled cells in more caudal area 23.
The most striking case is L. sinapis, which shows a gradual decrease in the diploid chromosome number from 2n = 106 in Spain to 2n = 56 in eastern Kazakhstan, resulting in a 6000 km wide chromosomal cline of recent origin [ 39].
Besides a significant increase in number, a gradual decrease in the diameter was observed in-line with Markus et al. (1987).
Assessment of caspase-3-like protease activity demonstrated a gradual decrease in the level of caspase-3 activation by Apo2L/TRAIL as the passage number increased.
Thereon, the increase in biomass concentration to 9.65 g/L and number of passes to 25 times demonstrated a gradual decrease in the release of specific protein at a constant value of 1,000 bar.
