The school's offering strategy depends on demands. We essentially offer those courses on our website. As soon as we get a demand that is significant enough and worth an actual offering, then we do those offerings.
In these particular cases, they are not offered that often, because the school is responsive to the actual demand. For example, we try to have a minimum number of participants in order to deliver the course. If we only have two or three people who are interested in the course, we wait until that number goes up and then we do an offering to meet the demand.