kitchens and habitable cellars and attics. About 38% of the total households were owner occupied, or in other words did not pay rent (though they may have a mortgage or a rent-to-own agreement). , there were 101 homes with 1 or 2 persons in the household, 709 homes with 3 or 4 persons in the household, and 496 homes with 5 or more persons in the household. The average number of people per household was 2.60 individuals. there were 472 single family homes (or 27.7% of the total) out of a total of 1,702 homes and apartments. There were a total of 14 empty apartments for a 0.8% vacancy rate. , the construction rate of new housing units was 4.4 new units per 1000 residents. In the 2007 federal election the most popular party was the SVP which received 47.4% of the vote. The next three most popular parties were the SP (16.3%), the FDP (11.8%) and the CVP (9.1%). The entire Swiss population is generally well educated. In Birr about 61.6% of the population (between age 25–64) have completed either non-mandatory upper secondary education or additional higher education (either university or a Fachhochschule). Of the school age population (), there are 334 students attending primary school, there are 156 students attending secondary school in the municipality. The historical population is given in the following table: Heritage sites of national significance The grave site of Heinrich Pestalozzi, at Pestalozzistrasse 2 is listed as a Swiss heritage site of national significance. Economy , Birr had an unemployment rate of 2.84%. , there were 23 people employed in the primary economic sector and about 6 businesses involved in this sector. 1,556 people are employed in the secondary sector and there are 25 businesses in this sector. 566 people are employed in the tertiary sector, with 58 businesses in this sector. there was a total of 1,859 workers who lived in the municipality. Of these, 1,407 or about 75.7% of the residents worked outside Birr while 1,722 people commuted into the municipality for work. There were a total of 2,174 jobs (of at least 6 hours per week) in the municipality. Of the working population, 11% used public transportation to get to work, and 49.6% used a private car. Birr's economy is dependent mainly on industry: among other businesses, ABB, GE and IC Interconnex can be found here. The regional airfield Birrfeld (Sport