up 19.2% of the population, while adults (20–64 years old) are 62.1% and seniors (over 64 years old) make up 18.7%. In 2015 there were 4,418 single residents, 4,619 people who were married or in a civil partnership, 519 widows or widowers and 673 divorced residents. there are 3,452 households in Sarnen. In 2014 there were 4,338 private households in Sarnen with an average household size of 2.32 persons. Of the 1,957 inhabited buildings in the municipality, in 2000, about 47.6% were single family homes and 26.7% were multiple family buildings. Additionally, about 24.4% of the buildings were built before 1919, while 14.9% were built between 1991 and 2000. In 2013 the rate of construction of new housing units per 1000 residents was 5.75. The vacancy rate for the municipality, , was 0.18%. Historic population The historical population is given in the following table: Heritage sites of national significance Sarnen is home to 10 sites that are Swiss heritage sites of national significance. These include three religious buildings; the Ossuary of St. Michael, the parish church of St. Peter and Paul, the Church of St. Martin. Two houses and a tower, the double house am Grund and Grundacher and the Hexenturm are on the list. The remainder of the list contains the Cantonal Rathaus, the musical collection of the Frauenkloster, the Landenberg armory and the State Archives of Obwalden. The entire small city of Sarnen, the hamlet of Ramersberg and the Kirchhofen area are part of the Inventory of Swiss Heritage Sites. Sarnen today The town of Sarnen has been experiencing steady growth over the past years. It has become more attractive due to its proximity to Lucerne. Many commuters work in Lucerne and use the motorway or railway service to get to work. Among companies active in Sarnen include SIKA AG (Specialty Chemicals), Leister Technologies (heated-air tools) and Nahrin AG (healthy nutrition). Economy Sarnen is a small sized regional center. , there were a total of 8,182 people employed in the municipality. Of these, 366 people worked in 144 businesses in the primary economic sector. The secondary sector employed 2,058 workers in 151 separate businesses. In 2014 a total of 1,176 employees worked in 146 small companies (less than 50 employees). There were 4 mid sized businesses with 561 employees and 1 large business which employed 321 people. Finally, the tertiary sector provided 5,758 jobs in 987 businesses. There