São Marcos da Serra lost 169 souls during the last 10 years. The total amount of residents counted in the Censos 2011 was 1366 (1535 in 2001). For the total Algarve region there was an increase of residents of 13,9% to 450.484. The parish of Alcoutim lost the most inhabitants, namely 23,2%. The council of Silves as a whole now has 37.087 residents.