* Country: School systems in different countries have different calendars.
* State/Province: Even within a country, individual states or provinces set their own school calendars.
* District: Even within a state or province, individual school districts may have slightly different start dates.
* Specific School: Sometimes even schools within the same district might have slightly varying schedules.
To find out when school started in 2016, you'd need to specify the location (country, state/province, and ideally the school district or even the specific school).