A population of a town is divided into three age classes: less than or equal to 20 years old, between 20 and 40 years old, and greater than 40 years old. After each period of 20 years, there are 80 % people of the first age class still alive, 73 % people of the second age class still alive and 54 % people of the third age Hare still alive. The average birth rate of people in the first age class during this period is 1.45 (i.e., each person in the first age class, on average, give birth to about 1.45 babies during this period); the birth rate for the second age class is 1.46, and for the third age class is 0.59, respectively. Suppose that the town, at the present, has 10932, 11087, 14878 people in the three age classes, respectively.