It returns 10, because that is usually the default specified at your site “read” settings (IIRC) and is used obviously explicitly for the front end, but also as default for the number of posts returned by wp_query. What you are looking for is the number_of_posts (don’t trust me, check the docs) argument for the query.
Aside, not sure what is it you are trying to do, but using LIKE will make your queries slow. Whatever you are trying to do, there must be a better way (unless this code will run only once, and then maybe performance is not an issue)