Publisher's audiences on Facebook have seen a rapid decline.

New data from market intelligence firm SimilarWeb has shown that there has been a huge drop in traffic for almost half of publishers active on Facebook.

The decline in traffic came before the social media giant announced changes to its algorithm, which will reduce the amount of publisher content in users' news feeds, according to SimilarWeb.

139 out of the 300 biggest publishers on Facebook have been their traffic decline year on year, according to SimilarWeb.

Big names such as BuzzFeed, Bleacher Report, Huffington Post, and Elite Daily have suffered.

Buzzfeed has seen traffic fall by 11.5% from 227.6M in the first quarter of 2015 to 201.3M in the first quarter of 2016.

Mashable saw it's traffic fall by 17% in the same period to 51.8M, while MSN's traffic fell by 45% to 33.6M.