Facebook Surprise: Companies’ Posts Now Reach Only 6% of Followers

This has always puzzled us - the way Facebook controls who sees what is shared on a Page on Facebook, in spite of the fact that the Company spent money to get fans to like the page in the first place. The reach percentage has been dropping heavily, and now, only 6 in 100 fans see updates from pages they liked (Source)

So don't say 'Like Us on Facebook'. It doesn't matter that much any more.