The phrase "demonstrated a tendency" is correct and usable in written English.
It is typically used to describe a behavior or habit that someone consistently displays. Example: Throughout his career, the athlete has demonstrated a tendency to push himself to his physical limits, often resulting in impressive performances on the field.
The Burke brothers are the second generation of a family that has demonstrated a tendency toward business achievement.
To make matters worse, English courts have demonstrated a tendency to accept jurisdiction in these cases even when the plaintiff's connection to England appears wafer-thin.
In the past two years, the former president has demonstrated a tendency to criticise Obama in order to bolster his wife, and to speak out-of-turn.
He has demonstrated a tendency to over think every reporter's question like he's planning the final move in a chess match against Bobby Fisher.
Patients demonstrated a tendency to sustain their weight on the foot less affected by dyskinesia, probably as a compensatory mechanism.
Micro-Raman spectra acquired from the nano-composite DLC coatings demonstrated a tendency of graphite formation of the transfer film.
Capitalism has demonstrated a tendency to politicise ever-growing areas of life, from the environment to the genetic code, and the profusion of "new social movements" since the 1960s reflects this.
The philanthropy world relies on discretion and good judgment, but Neilson has demonstrated a tendency toward self-promotion frequenting the Clinton Global Initiative, tweeting inceself-promotion frequentingomplishmenthe writing a regular Clintonin the HuffinGlobalost.
Nowadays, an increasing number of researchers have demonstrated a tendency to choose hybrid CPU GPU hybrid computing as a high performance computing alternative.
The results demonstrated a tendency for greater SNC in Lewis rats and then slower recovery from the unexpected loss of reward relative to the Fischer rats.
Indeed, immigrants from Java, Celebes, and Sumatra demonstrated a tendency to assimilate to the existing Malay community over time, a process that steadily accelerated with the rise of Malay nationalism and vernacular education in the 1930s.
