Define a period

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How many working days in year 1981?

Here is the detail of the calculation:

Because 1981 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 13 public holidays that do not fall during a weekend and we obtain 248 working days in 1981.

Here is the list of these 13 public holidays:

1. Año Nuevo : Thursday, 1 January, 1981
2. Jueves Santo : Thursday, 16 April, 1981
3. Viernes Santo : Friday, 17 April, 1981
4. Día del Trabajo : Friday, 1 May, 1981
5. Día de San Pedro y San Pablo : Monday, 29 June, 1981
6. Día de la Fuerza Aérea : Thursday, 23 July, 1981
7. Día de la Independencia : Tuesday, 28 July, 1981
8. Día de la Independencia : Wednesday, 29 July, 1981
9. Batalla de Junin : Thursday, 6 August, 1981
10. Combate de Angamos : Thursday, 8 October, 1981
11. Día de la Inmaculada Concepción : Tuesday, 8 December, 1981
12. Batalla de Ayacucho : Wednesday, 9 December, 1981
13. Navidad : Friday, 25 December, 1981

And here are the 3 public holidays falling on a weekend:

1. Batalla de Arica y Día de la Bandera : Sunday, 7 June, 1981
2. Día de Santa Rosa de Lima : Sunday, 30 August, 1981
3. Día de Todos los Santos : Sunday, 1 November, 1981