After Facebook admitted last December that post reach was declining and started encouraging the purchase of ads, it was Social@Ogilvy's turn to release a study conducted between October 2013 and February of this year, in which the company analyzed pages from 106 brands in various countries.
The research shows that the average reach of organic posts dropped from 12.05%, in October, to 6.15%, in February. Among 23 pages analyzed with more than 500,000 likes, the drop went from 4.04% to 2.11%. We can see that, in just four months, the decline was roughly 50%.
It's worth remembering that two years ago Facebook stated that about 16% of a page's fans organically viewed its posts.

With the drop in organic reach of Facebook posts, it's now practically impossible for a brand to operate on the social network without investing in advertising.
Companies will increasingly need to plan strategically and professionalize their social media management, so that the money invested delivers a good return and the set goals are achieved.
Check out the full study at http://bit.ly/1i3ZDx4