At least two context periods of an OCW annual report must contain element 'xbrli:instant' as a child of 'xbrli:period' and the date values must be the end dates of the current reporting year and the previous reporting year. At least one context MUST contain elements 'xbrli:startDate' and 'xbrli:endDate' as a child of 'xbrli:period' and the date values MUST be the start date of the reporting year and the end date of the reporting year respectively. Period instant values must be December 31 in the year 2016, 2017, 2018, 2019, 2020, 2021 or 2022. Period duration values must be January 1 and December 31 within in the same year 2016, 2017, 2018, 2019, 2020, 2021 or 2022. Contexts which do not refer to any dimensional values or only to 'Financial statements type', MUST refer to the duration of the current reporting year. Contexts with dimensional value 'Actuals' MUST refer to the current reporting year or the previous reporting year. Contexts with dimensional value 'Estimates' MUST refer to the current reporting year. Contexts with dimensional value 'Forecast' MUST refer to coming reporting years. Contexts with dimension 'Segment reporting' MUST refer to the duration or the end balance of the reporting year. If item 'rj-i:DocumentRelatesToIndividualEntityOrGroup' (Financial statements type) contains value 'Enkelvoudig' (Separate), then dimension 'Financial statements type' MUST only be reported with value 'Enkelvoudig'. Items within a typed dimension which are part of regular individual specifications MUST refer to the current reporting year, which includes the current year start balance. Movement items of movement schedules MUST refer to the duration of the current reporting year. Balance items containing maturity or other risk assessments, MUST refer to the end balance of the current reporting year.