In Scotland, it is usually only held at the end of S6 (ages 17/18) because all high schools in Scotland have pupils up to age 18 years, whereas elsewhere in the UK many students have to go to college to study for A-Levels. Proms are usually held in June, after the end of year exams, although in Northern Ireland they are usually held in the wintertime near the start of the school year. At Scottish formal events, boys usually wear kilts (kilts are also often seen in the other Celtic regions) and Highland dress outfitters often sell out in an area around this time of year due to demand from school events. Also in Scotland, it is customary for traditional Scottish country dancing (part of the curriculum of all secondary schools) to be included.