Returns the number of weeks in a year.
This function is only available if the Analysis AddIn is installed.
- returns the number of weeks in the year in which date lies.
- A week is considered to start on Monday, and is considered to be in the year if most of its days are in that year.
- returns 52, the number of weeks in 2010.
- returns 53, the number of weeks in 2009. In 2009, both 1st January and 31st December fall on a Thursday; the weeks containing 1st January and 31st December both have most of their days in 2009, and therefore both are counted.
- WEEKSINYEAR is not part of the forthcoming ODFF international standard, and should not be regarded as portable. It is not available in Excel.