The researchers found the average engagement rate (likes and comments divided by follower count) per post is now around 2%, down from 3% a year ago.
The decline in engagement began in November 2018, around when Instagram announced a new effort to remove fake accounts from the service.
Engagement by follower count and post type
Not surprisingly, engagement rate tends to vary significantly based on follower count, with the smallest accounts (fewer than 5,000 followers) garnering the highest average engagement rate.
Carousel posts have a higher average engagement rate than image and video posts, the analysis found.
Profiles with more than 100,000 followers published 241 Instagram posts, on average, over the past year, whereas accounts with under 5,000 followers published fewer than 50 posts, on average.
About the research: The report was based on data from an analysis of more than 7.4 million Instagram posts published by 31,033 brand profiles of different sizes between 2014 and 2019.