In the date of manufacturing of a tyre, as week and year, what is considered as first day? Sunday or Monday?

In UN Global Technical Regulation (UN GTR) No.16, point 3.2.1.3 states that “The DDDD with 4 digits represents the week and year of manufacture, also known as the date code. The first two symbols shall identify the week of the year by using "01" for the first full calendar week in each year, "02" for the second full calendar week, and so on. The calendar week runs from Sunday through the following Saturday. The final week of each year shall include not more than 6 days of the following year. The third and fourth symbols shall identify the year. Example: 0110 means the first week of 2010.”

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