How many working days in year 1966?
Here is the detail of the calculation:
Because 1966 is not a leap year, it has 365 days.
Let's remove 53 saturdays and 52 sundays. It remains 260 days.
Now, let's remove 10 public holidays that do not fall during a weekend and we obtain 250 working days in 1966.
 Here is the list of these 10 public holidays: 
 
 1. Sexta-Feira Santa : пятница, 8 апрель, 1966 
2. Dia da Liberdade : понедельник, 25 апрель, 1966 
3. Corpo de Deus : четверг, 9 июнь, 1966 
4. Dia de Portugal, de Camões e das Comunidades Portuguesas : пятница, 10 июнь, 1966 
5. Dia de Santa Isabel : понедельник, 4 июль, 1966 
6. Assunção de Nossa Senhora : понедельник, 15 август, 1966 
7. Implantação da República : среда, 5 октябрь, 1966 
8. Todos os Santos : вторник, 1 ноябрь, 1966 
9. Restauração da Independência : четверг, 1 декабрь, 1966 
10. Dia da Imaculada Conceição : четверг, 8 декабрь, 1966 
And here are the 4 public holidays falling on a weekend:
1. Solenidade da Santa Mãe de Deus : суббота, 1 январь, 1966 
2. Páscoa : воскресенье, 10 апрель, 1966 
3. Dia do Trabalhador : воскресенье, 1 май, 1966 
4. Natal : воскресенье, 25 декабрь, 1966