According to the  2011 census  Sirmaur district has a  population  of 530,164,  roughly equal to the nation of  Cape Verde .  This gives it a ranking of 542nd in India (out of a total of  640 ).  The district has a population density of 188 inhabitants per square kilometre (490 /sq mi) .  Its  population growth rate  over the decade 2001-2011 was 15.61%.  Sirmaur has a  sex ratio  of 915 females  for every 1000 males,  and a  literacy rate  of 79.98%