demogr.sq

Demographic evolution

First contact

The population of Switzerland and its evolution since 1990 is displayed in different graphics. The situation in 1990 is shown as a pyramid (top left); the evolution of the total population is shown as a function of time (bottom left), as well as the ratio between the active people and the retired people (bottom right). At the beginning, the fertility (number of babies per woman during her life) is 1.56, a value corresponding to 1990, much lower than what would be required to keep a constant population, as you can see in the population evolution graphics. If you increase it to 2.1 (move the middle slider to the right in the upper right figure), the total population stabilizes at around 7.4 millions. You can drag the green line in the bottom figures to see the pyramid for another year. In the Population figure, you can move the mouse cursor over the pyramid (the blue line for men or the pink line for women) to display the corresponding year of birth. You can also drag up and down the small horizontal lines to change the limits of the groups of active and retired peoples.

Figures

Population

Population pyramid, with the men in blue on the left and the women in pink on the right. The pyramid represents the population for a given year, the current year represented by a green line in figures which show functions of time. The vertical axis is the age, from 0 to 99 years old; the pyramid is made of slices whose thickness is one year. The horizontal scale (number of people having the same age) represents thousands of people. The birth year of the slice under the mouse is displayed in the status bar at the bottom of the window. You can go forward in time by dragging the pyramid upward (you make the slice under the mouse older).

The short green horizontal lines represent the limits of the groups defined for the figure "Group 1/Group 2 Ratio". You can drag them to redefine the groups.

Fertility

The fertility represents the average number of babies (boys in blue and girls in pink) each woman gives birth to in function of her age. The curves are triangular and do not correspond to the reality, but this has a very small effect on the simulation. You can drag each point of the triangle to observe the effect of having children later.

Mortality

The mortality represents the probability to die in one year as a function of the age.

Men/Women Ratio

The men/women ratio is displayed as a function of the age. It drops to zero, because the mortality is higher for men than for women for old people.

Population Evolution

Remaining figures represent the result of simulation of the evolution of the population based on the initial population, the mortality and the fertility, which are supposed to be fixed. The population evolution represents the total population as a function of time. The vertical green line is the current year and can be dragged to see the evolution of the population pyramid.

0-14 Evolution

The 0-14 evolution represents the children up to 15 year old as a function of time.

65-99 Evolution

The 65-99 evolution represents the people older than 65 years old as a function of time.

Group 1/Group 2 Ratio

The group 1/group 2 ratio represents the ratio between to groups of people defined by their ages as a function of time. By default, the group 1 is the active people (between 20 and 65 years old, the current retirement age in Switzerland for men) and the group 2 is the retired people (older than 65). The group limits can be changed in the population pyramid or in the Settings menu (Group Ages).

Parameters

The figure Parameters shows three sliders for the current year, the global fertility (number of babies per woman) and the proportion of female babies (usually slightly smaller than 0.5).

Settings

Separate men/women

The figure representing simulation results can show either the total or two curves for men (in blue) and women (in pink).

Current Year

The current year, which corresponds to the population pyramid, can be set in a dialog box. Large numbers require may require a long simulation.

Fertility

The global fertility (number of babies per woman) can be set in a dialog box. The fertility which would assure a constant population is displayed; it is slightly over two, because a small percentage of girls die before having children.

Girl Birth Ratio

The proportion of girl babies can be set in a dialog box.

Group Ages

The age of the groups whose ratio is displayed in the figure Group 1/Group 2 Ratio can be set in a dialog box. Each group is defined by a vector of ages; use colons to define range (e.g. [20:64], [65:99] for the default settings), and commas for several ranges (e.g. [0:19,65:99] for children and retired peoples).

Use Current Year as Initial Conditions

All simulation are based on an initial population, which at the beginning corresponds to the census of 1990. Simulating over a large time range can be slow. By choosing Use Current Year as Initial Conditions, you change the starting point and reduce the simulation length. Note that afterwards, you cannot display data corresponding to years before the new initial conditions.