Define a period

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How many working days in year 1975?

Here is the detail of the calculation:

Because 1975 is not a leap year, it has 365 days.

Let's remove 52 saturdays and 52 sundays. It remains 261 days.

Now, let's remove 9 public holidays that do not fall during a weekend and we obtain 252 working days in 1975.

Here is the list of these 9 public holidays:

1. Nieuwjaarsdag : Wednesday, 1 January, 1975
2. Paasmaandag : Monday, 31 March, 1975
3. Dag van de Arbeid : Thursday, 1 May, 1975
4. Hemelvaartsdag : Thursday, 8 May, 1975
5. Pinkstermaandag : Monday, 19 May, 1975
6. Nationale Feestdag : Monday, 21 July, 1975
7. Onze-Lieve-Vrouw Hemelvaart : Friday, 15 August, 1975
8. Wapenstilstand : Tuesday, 11 November, 1975
9. Kerstmis : Thursday, 25 December, 1975

And here are the 2 public holidays falling on a weekend:

1. Feest van de Franse Gemeenschap : Saturday, 27 September, 1975
2. Allerheiligen : Saturday, 1 November, 1975