Brand activity on Facebook increased by 36 percent last year, but Instagram saw the greatest uptick in new follower gains and user interaction, according to a social benchmark study by San Francisco-based media analytics company Quintly that gauged growth among the three largest social networks.

Facebook, which still maintains the largest user base of any social media network, saw daily post activity increase by far greater numbers than Instagram or Twitter, indicating marketers still rely heavily on the site. Facebook posting frequency grew by 36 percent in 2015, compared to 14 percent growth on Instagram and a two-percent decline at Twitter.

Quintly Social Benchmark StudyThe Quintly study shows that the most daily Facebook posts came from pages the boast between one million and 10 million fans — where an average of 7.93 posts occurred each day — while profile pages holding more than 10 million fans saw an average of 5.89 posts a day, and pages with between 100,000 and one million fans posting an average of 4.10 times a day.

Facebook exhibited almost constant growth throughout the year. However, the numbers indicate the site may have reached a saturation point: profile pages with the smallest number of fans (between one and 1,000) saw the greatest gains in followers, while pages with the most number of fans (10 million and more) actually saw a decrease of nearly 6 percent. Moreover, the highest interaction rate among users typically came from Facebook pages that had the smallest number of followers.

While Instagram yielded fewer followers and average daily posts, the study found that the photo-sharing site now holds the highest follower growth rate among the three social networks and also currently boasts interaction rates many times higher than Facebook or Twitter. Brand profiles grew significantly on Instagram last year, and like Facebook, the more followers a page has, typically the more daily posts that page shares. Unlike Facebook, however, Instagram profile pages seem to be gaining more followers regardless of how many current followers that page has.

Also like Facebook, the highest interaction rates were also seen in the smallest profile pages. However, interaction rates were greater on Instagram than Facebook or Twitter regardless of follower numbers.

The Quintly study analyzed more than 180,000 profiles on Facebook, Instagram and Twitter between January and December 2015.

View the study here.