Just click/select the "Like" app and you will see a number of "Total Likes" and
"People Talking About This". Take the number of people “talking about this” and divide it by the number of “Likes” . For example 448/1809=0.24765 that would be 25% engagement. I also use this to spot people that have "bought" fans. If you have 4000 likes and 2 as talking about with clear content it is a good chance you bought fans or just very very boring. :)
For most small businesses 1 to 5% is doing very well. Remember the other % that is just observing is also important since many of the new customers come from there.
Share how you have gained more engagement on your page and more business on your Facebook page. I may show it off in my classes to get you more "Likes". Remember the goal is more of the customers you want not just "Likes".And "Yes" people both show up at my classes and hire me from my Facebook page.