Define a period

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How many working days in year 1991?

Here is the detail of the calculation:

Because 1991 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 8 public holidays that do not fall during a weekend and we obtain 253 working days in 1991.

Here is the list of these 8 public holidays:

1. Nieuwjaar : Tuesday, 1 January, 1991
2. Goede Vrijdag : Friday, 29 March, 1991
3. Tweede Paasdag : Monday, 1 April, 1991
4. Koninginnedag : Tuesday, 30 April, 1991
5. Hemelvaartsdag : Thursday, 9 May, 1991
6. Tweede Pinksterdag : Monday, 20 May, 1991
7. Eerste Kerstdag : Wednesday, 25 December, 1991
8. Tweede Kerstdag : Thursday, 26 December, 1991

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

1. Eerste Paasdag : Sunday, 31 March, 1991
2. Eerste Pinksterdag : Sunday, 19 May, 1991