At what age is it okay to tell ghost stories to kids? Is it healthy to, though?

I enjoyed scary movies and ghost stories growing up. Sharing the experience with my parents or older brother made it more fun. These stories are cathartic to some point if it's a healthy amount of spook. Here are some stories you can share: http://www.sheknows.com/parenting/articles/1016713/scary-halloween-stories-for-kids