"demonstrate a trend" is a correct and usable phrase in written English.
You can use it to describe an action that shows a general pattern of development or movement. For example, "The sales figures demonstrated a trend of decreasing profits year-over-year."
The Third Metric conference and the American Express study demonstrate a trend — or maybe the hope of a trend — that we can reinterpret success beyond the traditional signposts of wealth and concrete achievement.
Our data demonstrate a trend of adhesion force that is in accordance with R a in the process of chondrogenic differentiation.
The results demonstrate a trend in widespread disuse of the karez, with the notable exception of the Helmand and Kandahar provinces.
Our results demonstrate a trend for increased survival of first born premature infants when compared with offsprings of subsequent deliveries, and an association between advanced parity and the development of severe intraventricular hemorrhage.
A quick review of these three and the other solutions that were pitched demonstrate a trend towards targeting boys in the community, in school or through media.
We could demonstrate a trend toward slower RTs for the hands with increasing age of the subjects.
(Insert boilerplate caveat about individual extreme data points not sufficient for demonstrating a trend).
York County demonstrated a trend toward increasing thyroid cancer incidence beginning in 1995, approximately 15 years after the TMI accident.
Impact force demonstrated a trend toward significance (P = 0.14).
Locked plating demonstrated a trend towards increased nonunion rates when compared to RIMN.
An example of a CB for POPCs is the ´I COUGH´ study, which demonstrated a trend towards reduction in POPCs.
