From 1940 to 1960, the city's population increased to nine times that of the population at the turn of the century. During the 1940s the city's development vision was low-cost, low-density housing, each with its own well and septic system. The rapid growth in population was in part due to the post-World War II boom and subsequent birth of the baby boomer generation. In 1947, the first fire station was constructed and equipped at a cost of $24,000 and the Bloomington Volunteer Fire Department was established with 25 members.