a total of 320 inhabited buildings. There were 38 two family buildings (11.9%), 13 three family buildings (4.1%) and 18 multi-family buildings (or 5.6%). There were 341 (or 30.8%) persons who were part of a couple without children, and 500 (or 45.1%) who were part of a couple with children. There were 54 (or 4.9%) people who lived in single parent home, while there are 11 persons who were adult children living with one or both parents, 4 persons who lived in a household made up of relatives, 8 who lived in a household made up of unrelated persons, and 28 who are either institutionalized or live in another type of collective housing. The vacancy rate for the municipality, , was 3.16%. , the construction rate of new housing units was 10.6 new units per 1000 residents. there were 602 apartments in the municipality. The most common apartment size was the four-room apartment of which there were 157. There were 30 single-room apartments and 133 apartments with six or more rooms. the average price to rent an average apartment in Salenstein was 1228.12 Swiss francs (CHF) per month (US$980, £550, €790 approx. exchange rate from 2000). The average rate for a one-room apartment was 639.30 CHF (US$510, £290, €410), a two-room apartment was about 848.61 CHF (US$680, £380, €540), a three-room apartment was about 1069.35 CHF (US$860, £480, €680) and a six or more room apartment cost an average of 1805.63 CHF (US$1440, £810, €1160). The average apartment price in Salenstein was 110.% of the national average of 1116 CHF. In the 2007 federal election the most popular party was the SVP which received 47.36% of the vote. The next three most popular parties were the CVP (13.41%), the FDP (12.83%) and the SP (11.18%). In the federal election, a total of 444 votes were cast, and the voter turnout was 54.4%. The historical population is given in the following table: Heritage sites of national significance There are three castles; Arenenberg (with chapel and Napoleon Museum), Eugensberg and Louisenberg as well as the pilgrimage chapel of St. Aloysius in Mannenbach on Louisenbergstrasse 14 that are listed as Swiss heritage sites of national significance. The villages of Salenstein and Mannenbach and the Untersee region (including Ermatingen, Gottlieben, Kreuzlingen, Salenstein and Tägerwilen) are designated as part of the Inventory of Swiss Heritage Sites. Arenenberg Castle was built in the early 16th century