Siat had a population (as of 2011) of 171. , 2.8% of the population was made up of foreign nationals. The age distribution, , in Siat is; 25 children or 13.2% of the population are between 0 and 9 years old and 25 teenagers or 13.2% are between 10 and 19. Of the adult population, 8 people or 4.2% of the population are between 20 and 29 years old. 35 people or 18.5% are between 30 and 39, 20 people or 10.6% are between 40 and 49, and 15 people or 7.9% are between 50 and 59. The senior population distribution is 28 people or 14.8% of the population are between 60 and 69 years old, 21 people or 11.1% are between 70 and 79, there are 11 people or 5.8% who are between 80 and 89, and there is 1 person who is between 90 and 99. In the
2007 federal election the most popular party was the
CVP which received 49.8% of the vote. The next two most popular parties were the
SVP (31.2%) and the
FDP (8.8%). ==References==